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A round up of all of the latest Universeal UK news, tamper-evident security industry updates and product guides to make your supply chain more secure.
What are Security Seals? Understanding Types, Uses, and Importance
Security seals are essential tools in safeguarding goods, ensuring integrity, and preventing unauthorised access across various industries. In this guide, we will dive into what security seals are, their different types, applications, and their significance in today's security landscape.
Sunday, April 20, 2025
Top 10 Applications for Metal Cable Seals
We have put together the Top 10 Use Cases for Cable Security Seals, and explain in each case why cable seals are particularly suited for these types of applications.
Cable security seals are flexible and strong types of security seals popular across all types of industries, including freight and transport, food & pharmaceutical, industrial and manufacturing and other sectors. We have put together the below Top 10 Use Cases for Cable Security Seals, and explain in each case why cable seals are particularly suited for these types of applications.
Top 10 Use Cases for Metal Security Seals
| Use Cases of Cable Security Seals | Illustration |
|---|---|
Road Haulage / Trailer Security Cable seals are often used to lock through the locking hasps of road trailer doors, as a stronger solution and more tamper-evident solution than easier breaking pull-through or fixed length trailer seals which can be used alternatively. Our flexiGrip 150M seal is a HMRC Customs accepted seal, and road freight transiting the UK-EU customs borders can utilise customs-accepted cable seals as a cost-effective security seal solution for cross-border road shipments. |  |
Shipping Containers ISO17712 High Security Cable seals are strong barrier seals suitable for sealing of shipping containers transiting customs borders. Cable Seals are sometimes preferred to more conventional bolt seals for shipping containers to provide increased security, particularly for high value shipments involved in food/drink and pharmaceutical logistics: i. Extra-long cable seals can seal around the vertical locking bars, which can provide superior security compared to sealing at locking hasps ii. Our specialised double-locking Flexigrip 500MD is a heavy-duty cable seal which provides a double locking mechanism, for increased security shipments. |  |
Air Cargo Containers Air cargo containers are often subject to vibration, knocks and shocks during air transport and ground movements, and as such lower-strength plastic pull-through seals are not often strong enough to provide effective tamper-evident security. Cable seals provide higher strength security to ensure that seals do not open whilst in transit, providing a full chain of custody of sealed air cargo enclosures from point-to-point. |  |
Rail Cars Cable seals are ideal for sealing individual rail freight car doors. Our range of cable security seals have rugged design features to ensure chain of custody during rail... |
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Types of Container Seals
Most shipping containers transiting around the world will be sealed by way of a High-Security Bolt Seal, and with good reason. Bolt seals are inexpensive but strong barrier seals which cannot be opened except by application of heavy-duty bolt cutters which physically and permanently destroy a security seal, making reinstatement impossible. Bolt seals are required for international customs movements and must conform to internationally agreed standards for manufacturing good practice, strength and tamper-resistance, as stipulated under ISO17712 “High-Security” and C-TPAT Regulations.
However, bolt seals are not the only kind of security seal which can be used, and for certain types of shipments or in particular scenarios it is more suitable to use other types of security seals for sealing shipping containers, and in this guide we explain why this is the case.
| Type of CONTaiNER security seals | illustration |
|---|---|
Bolt seals are the original form of security seal for shipping containers. They are made up of two separate parts which include the bolt pin and the barrel, supplied together and with counterpart seal numbers engraved on each part. Container bolt seals are locked by pushing the pin into the barrel – the barrel has a self-locking system, and once sealed cannot be opened again; a bolt cutter must be used to open the seal, which permanently destroys the seal and makes reinstatement impossible. |  |
The Fork Seal is another type of seal fully-compliant to ISO17712:2013 HSS (high security seal) for sealing shipping containers. Fork seals provide complete wrap-around protection of container locking bars of any size and offers the highest form of container security; the strong steel can only be cut at the designated cutting point using the very heavy-duty bolt croppers. As one of the stronger barrier seals available on the market today, Fork seals are preferred by some users when sending high-value or high-target shipments globally; for example, shipments of whiskey and other high-value food & drink specialities, as well as valuable or sensitive pharmaceutical shipments. |  |
Cable security seals, also known simply as ‘cable seals’... |
Types of Security Seals
The range and different types of security seals and tags can be confusing to the uninitiated, so we have produced the below quick visual guide for understanding some of the key differences, and how particular types of security seals might be suited to use cases in your organisation. For further help and assistance, please contact us at sales@universeal.co.uk
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| Plastic Indicative Seals, 2 types: (1) Pull-Through Seals seal through locking chamber & pull progressively tighter, suitable for sealing of mail & cash bags; (2) Fixed Length Seals form a fixed loop, suitable where over-tightening might cause accidental breakage in transit (such as trailer hasps). | Security padlock seals are fixed length seals which are small and suitable for sealing of small enclosures like trolley apertures, first aid and other equipment kits, security bag zippers etc. They can easily be sealed and broken by hand for quick and convenient application. | Bolt security seals provide barrier control for shipping containers. They consist of a counterpart barrel and pin with duplicate numbering, sealed together and requiring bolt cutters to remove. They must meet ISO17712 high security standards and are suitable for cross-border customs movements. |
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| Metal Cable seals are strong barrier seals, and in their heavier gauge options (Flexigrip 325M and Flexigrip 500M) are also ISO17712 'High Security' approved for customs movements. The pliable wire cable can be flexibly used to seal through hasps and around vertical locking bars, providing increased security. | Metal strip seals are useful option between plastic indicative seals and heavier duty cable and bolt seals - they provide a higher tensile strength of between 50KgF - 100KgF compared to plastic seals, but are most cost-efficient compared to cable and bolt seals. Their thin straps make them well-suited for sealing small apertures, such as TIR cords and railcars. | Meter wire seals are products suited to sealing utility (gas and electric) & taxi meters. They range from simple plastic and metal seals which can be crimped onto sealing wire with pliers, to more sophisticated self-locking seals with inner mechanism. Wire seals are produced with narrow gauge wire to fit through the small apertures of meters (<1mm). |
Choosing the Best Security Seal for the Job
With the range and breadth of security seals on the market, it can be very challenging for the uninitiated to know which seal to choose to best suit their needs. From the outset, it is recommended that the decision-maker considers the purpose of the security seal in relation to the application. Considering some of the fundamentals from the outset will help to select the right seal for the job…
…why is the user sealing the enclosure in the first place? Is it for loss prevention, safety purposes, product integrity, brand assurance...?
…what type of goods will be protected? What is the value of the goods?
…where is the seal going, and how? Cross-border shipments are subject to customs regulations which will affect the seals that can be used
…what kind of resistance is required? What are the consequences should if the security seal has been broken or tampered with?
…what environment is the seal being used in? What is the operating temperature? How long does the seal need to last for?
Answers to these questions will have a bearing on the material, form, shape, strength of the most appropriate security seal.
It should also be noted that a security seal alone cannot provide an iron-clad guarantee of integrity. No manufacturer anywhere in the world can say with complete certainty that – given enough time, appropriate circumstances, resources, skills and ingenuity – their security seals are undefeatable... but this is also true of safes, door looks, padlocks and alarms. Security seals should always be used as one layer within an ‘onion skin’ of security (view our guide to security protocols).
With this said, below we note some key characteristics of seals you should consider when choosing the most suitable. Try out our handy filtering tools shown on our main security seals category to find a product matching your needs.
| Seal Feature | Considerations |
|---|---|
| Design Type | Seals come in many forms... Pull-through Security Seals, Fixed-Length Security Seals, Security Padlock Seals, Barrier Seals (Cable Seals and Bolt Seals), Wire/Rope Meter Seals, and even Reuseable Electronic Seals. Security seals also include security tapes and labels, suitable for flat surfaces and edges on enclosures such as crates, cartons and pallets. Each type is designed for particular types of applications - for more information, see types of security seals. |
| Physical Fit (Diameter, Length and Flag Size) | Each security seal will have a particular tail or hasp diameter, an effective useable length, and a standard flag size for visibility of printed identification markings. Narrower seals are useful where seals must fit into smaller apertures, and for this many of our pull-through seals have smaller diameters, such as the MiniLock 570's 1.4mm tail thickness and UniTite 414's 2mm thickness. We also offer extra long seals, such as the UniStrap 412-XL (overall 51cm length) and UniTite 413 (overall 49cm length). In terms of flag size ("marking area"), we offer specialised security seals such as our UniFlag Security seal, which has a large format (108x56mm size). |
| Material | Common materials in use for security seals are polypropylene, nylon, aluminium and steel. Polypropylene is a popular choice for pull-through seals, as it offers a combination of strength, flexibility and wide operating temperatures. However, all types of plastic do become brittle at increasingly low temperatures, and do degrade when exposed to UV light, long-term saltwater exposure, solvents etc. Metal aluminium and galvanised steel cable seals provide more durability and strength where circumstances dictate, and we can also specify stainless steel cable grades for most demanding applications: see our Flexigrip 150M and Flexigrip 325M models. |
| Strength | Seals are specified for particular strengths – for certain applications such as fire extinguishers, kit bags and first aid trolleys it is desirable to have a very low break-strength so that seals can be broken in an emergency – for others, for example mail sack security seals, it is important that seals with strong break strengths are used so that bags do not burst open when under tension. There is a wide range of tensile strengths available, from 5KgF all the way up to 2000KgF, so understanding the possible forces relevant for your application is important for specifying the right kind of seal. |
| Level of Tamper-Evidence | We categorise our security seals as having either a Low, Medium or High degree of tamper-evidence, based on design and construction features, method and material of construction, and level of certification. |
| ISO Classification | Linked to the above, higher levels of security seals are often required for international freight movements - in particular, High Security Seals as classified under ISO17712:2013 regulations for international shipping container and freight movements. |
| Removal Method | Some applications require easy-access into a sealed enclosure, and for this we have security seals that can be removed easily by hand, either with low-break strengths (see our Fireseals) or tear-line features (see our Tracewaste Tear-Off and UniStrap 412LT). For other requirements, security seals need to be robust and should not be removed intentionally without simple tools such as scissors or tin-snips, such as our UniTite 413. In other scenarios, particular for barrier seals, we have our heavy-duty cable and bolt seals, products such as our Flexigrip 325M, Flexigrip 500M and Fork seals which necessitate the use of heavy-duty cutting tools like bolt croppers to remove. |
| Sustainability | Sustainability should of course be at the heart of every business, and security seals should be no exception. All of our plastic security seals are 100% recyclable, and we are increasing options for recycled content and biodegradable security seals on a regular basis. |
Universeal UK has been supplying security seals since 1992, and we are one of the leading organisations in the industry. Please email sales@universeal.co.uk for more information on our range and how we can assist. For advice on using security seals within a wider security program, please continue reading our next article in the series, Security Protocols: Making Security Seals work for You.
This article is the second of four, looking at how security seals can fit within your wider security protocols. View Series below...
- What are Security Seals?
- Choosing the Best Security Seal for the Job
- Security Protocols: Making Security Seals work for you
- Glossary – Understanding security seal terminology
Environmentally-friendly, biodegradable security seals
Universeal UK pioneers biodegradable security seals
Universeal UK has begun incorporating environmentally-friendly plastic technologies into our plastic security seals to mitigate against the environmental hazards of single-use plastics.
Awareness of the environmental damage caused by single-use plastics, especially in our rivers, lakes and oceans, has rightly taken centre-stage in the public consciousness in recent years. Whilst most security seals are manufactured from materials which are 100% recyclable, the difficulty of responsibly recycling security seals which might travel all over the world with their cargos has presented a major challenge for the security seal industry.
Formulating single-use plastics which can properly degrade into harmless by-products has been a major goal of the industry, but has been a technical challenge to solve. Whilst supposedly “biodegradable” and environmentally-friendly “green” plastic security seals have been around for years, unfortunately the materials they are made from have not always been the cure-all which some would claim.
The problem with many supposed green plastics is that they can actually contribute to the problem of plastic waste. For instance, “oxo-degradable” plastics have actually contributed to the problems of micro-plastics in recent years, and have been banned through many parts of the world. Similarly, other supposedly green “compostable” plastics only actually bio-degrade in special industrial composting facilities, which break the plastic down by using a combination of oxygen and heat. However, this means that if the plastic goes to normal landfill (of which around 80% of plastic still does) it will not biodegrade, as in such landfills there is not enough oxygen or heat to do the job of breaking the plastic down. The plastic therefore continues to persist for many hundreds or thousands of years in landfill. Alternatively, they are simply burnt and thereby release the carbon and other damaging substances which any other type of plastic would do. A further serious problem with these types of compostable plastics is that they cannot be recycled along with other types of conventional plastic – meaning that they can potentially cause more harm than good.
Over the last few years Universeal UK has been monitoring the development of technologies which can provide a better solution for single-use security seals. We are pleased to report that we have identified a revolutionary type of additive which can be incorporated into plastic security seals and can successfully biodegrade the plastic in the environments in which discarded security seals are commonly found: our landfill sites, or even worse, our oceans. The additive - which can be added to conventional plastic without affecting its properties - acts to break down the plastic even in anaerobic environments, once exposed to the types of bacteria commonly present in all types of conventional landfills, oceans and streams.
Once in contact with this bacteria, plastics can start breaking down as quickly as 30 days from their time of entering into the environment – this is in contrast to conventional plastic which persists for hundreds if not thousands of years. Test reports are showing that on average biodegradation is 200 times faster with the additive. By-products left behind are humus and methane (bio-mass and bio-gas), which are non-toxic; humus can actually be used as new soil to grow plants, and methane may be harvested into fuel. Independent third-party tests have shown that the additive conforms to ASTM 5511 testing standards, which is an internationally-recognised measure of biodegradation in anaerobic conditions prevalent in landfill environments. Reports showing biodegradation rates for particular samples are available upon request.
We are now offering production of the below security seal models with inclusion of special biodegradable Biosphere additive:-
 | TabLOCK 20cm and 30cm Multipurpose security seal available in two lengths, with/without tear-line... now available with Biosphere biodegradable additive. |
 | UNI411 Security Seal Multipurpose security seal for roll cages, trucks and trailers... now available with Biosphere biodegradable additive. |
Car Seals for Lockout of Safety-Critical Valves
“Car seals” are single-use security cable seals, so-called due to their alternative use in sealing railway cars, or wagons. Such car seals can also be used in the safe and effective lockout and isolation of industrial valves. Our Flexigrip 325M car seal is available from UK with unique sequential numbering and 1m length cable for safe and secure sealing of valves.
Car seals perform well as single-use lockout devices to seal a valve in the open or closed position, typically for long durations - for example, to permanently secure a sprinkler system valve. To remove the car seal, a cutting tool is required, after which the cable will splay, ensuring that the device cannot be re-used. This effectively prevents unauthorised use of the valves, where this may be dangerous without appropriate safeguards.
Below is a visual guide to the use of car seals for valve lockout:-
Securing the Skies - Security Seals for the Airline Industry
Security seals are a key component in the securing of global aviation logistics, ensuring that aircraft, airports and airline supply chains are secured against the issues of tampering, theft or bad practice. They serve as a means by which an audit history of logistics movements can be maintained so that authorised users might understand where risks under their area of influence might be managed and reduced.
Overview
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Security Seals in Use
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Airplane doors should be sealed overnight whilst unattended to ensure that no-one has accessed the aircraft without prior approval. Security labels can be used to seal the seam of the doors in this scenario to ensure that access is notified and recorded. Non-Residue Security Labels cannot be unpeeled or removed without the label delaminating, showing VOID through the surface of the label, but does not leave any unwanted residue on the aircraft itself. |
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| Air freight / air cargo containers are subject to rugged handling, logistics movements, in-flight turbulence, and more. Choosing the right security seal is therefore very important, and seals with sophisticated anti-tamper features and high-pulling strengths only should be used. Universeal UK recommends the application of single-use variable length cable seals in... |
Cargo Security: Sealing Vans, Trucks and Trailers
Securing your assets against theft and interference whilst in transit is more important than ever in our globally-connected world. Security seals are an important part of the security process; helping to ensure that your goods arrive at destination as expected, without delay.
Security seals come in various forms to suit particular applications, and in this article we run through the different types of seals which are suitable on various forms of road transport vehicles.
Transit and Small Van Security | |
 | Security LabelsSmall transit and other small courier vans do not feature locking hasps or other features which would allow for sealing by way of an indicative pull-tight or fixed length seal. Instead, non-residue security labels can be placed on the seam of vehicle doors, preventing access without removing the label and de-facing the surface, leaving a VOID message through the seal. Non-Residue labels have the advantage in that they do not leave a residue on the surface of the doors, avoiding damage to paintwork. |
Vans with Roller Door Shutters |
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 | Indicative Pull-Tite SealsVans and other vehicles with roller-shutter doors feature hasp and staple-style locking arrangement. For these types of locks, we recommend use of a pull-tite or “pull-through” tamper-evident seal, which can be secured tightly around the mechanism, preventing interference by opportunists. Pull-through seals are available in many different sizes and configurations. We hold most items in our UK warehouse; alternatively, we can customise with your bespoke marking, logo and custom numbering. |
Articulated Lorry Trailer Doors | |
 | Fixed-Length / Ring SealsTrailer doors are available with a number of different locking mechanisms, and so the preferred security seal will depend on the mechanism in question - either pull-through or fixed-length seals are recommended. Fixed-length or "ring" seals, form a secured loop through a locking aperture. Ring seals do not “pull tight” around the locking arrangement, meaning that they can be freely rotated, checked and inspected for signs of tampering more easily... |
Security Seals and Identification Tags: what’s the difference?
Security Seals and Identification Tags: what’s the difference?
To put it simply, security seals are used in applications in which a tamper-evident solution is required to ensure that the sealed items cannot be accessed without the knowledge of the authorised user. Identification ties, on the other hand, are products designed to fasten around bags, boxes and other items to keep them closed – they are not designed to be tamper-proof, although they can be uniquely printed to identify assets or communicate information to a user.
What is a security seal?
Security Seals; as the above suggests, are used to secure something: this could be anything from sealing a locking hasp on a door or a first aid kit, to a shipping container or oil drum.
A true security seal is not exactly designed to stop unauthorised access to something but rather to make it extremely difficult to access a sealed enclosure without the seal showing signs of having been tampered. This is achieved by engineering the security seal – and in particular its locking mechanism – in such a way that external manipulation is very difficult once the seal is in situ (without simply breaking the seal). As an example, our Tracewaste seal features an encapsulated locking mechanism to prevent tampering.
However, tamper-evidence alone isn’t enough. More often than not a security seal will have its own unique serial number. As an example, a logistics haulier might wish to seal curtain-sided lorries with a uniquely numbered security seal; record the particular serial number at its origin; and then ensure that the same seal is intact without signs of tampering at the arrival destination. This reduces the risk that unauthorised users might replace a security seal whilst in transit. As well as sequential numbering, users might opt to use their company logo / other markings to uniquely identify the seal.
Not all security seals are made equal.
Security seals are designed with particular applications in mind. Some seals, such as the Fireseal are designed for very low-break strength and are purely “indicative” in nature. They are easily opened, and particularly suited to applications where immediate access is required: sealing fire extinguishers, medical crash trolleys, and spill kits are all typical examples of their use.
Certain seals are intermediate in nature: combining indicative tamper-evidence with a medium-to-high level of physical strength (for example, featuring a pulling resistance of greater than 40 Kgf). Such seals require removal by way of cutting snips or by way of a specially designed tear-able parts of the seal. Our UNI-412 and UNI-413 seals are examples of such products.
At the other end of the scale, some security seals are designed with much higher physical resistance in mind, so that only specialist bolt and cable cutters are suitable to remove the seal. Specifically, in most cases where shipping containers are being moved internationally, security seals must adhere to the “high-security” ratings applicable within the ISO 17712:2013 standards. For example, our Locktainer 2020SH bolt seal is fully-compliant with ISO17712 and CT-PAT regulations. These regulations ensure that container seals have been rigorously tested for their strength properties and their resistance to common methods of interference.
You can read more about such compliance in our blog: Compliance with C-TPAT and ISO 17712:2013 Standards for High-Security Seals.
Security seals also come in different shapes and sizes. As well as the pull-through plastic seals and high-security bolt seals mentioned above, there are number of key categories for particular uses. For example, cable seals are used as very strong yet flexible, adjustable length seals with high pulling strengths, suitable for heavy-duty applications such as oil drums, high-security shipping, chemical tankers and many more applications.
Yet another type of security seal is our adhesive security labels and tape range, which can be applied to flat surfaces and which, when removed, leaves behind a residue as its tamper evidence. The residue will often have a word repeated in it such as ‘opened’ or ‘void’. Alternatively, the label itself can delaminate, so that this wording appears in the label itself, leaving the applied surface untouched.
Certain types of products also incorporate security seals and tamper-evidence within their design – for example, our re-usable security envelopes and mail pouches incorporate locking mechanisms which can be sealed using disposable security seals which can be snapped off and replaced.
Finally, a growing trend looking forward is towards electronic security:- electronic seals which incorporate technologies such as unique number generation for re-use, GPS trackers and RFID technology. IntelleSeal T is an example of an electronic seal for use on trucks and trailers.
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What are identification ties?
Identification ties and tags are normally used to fasten, enclose and identify a particular object or asset; or to communicate particular information about whatever is tagged.
The emphasis for identification ties is not in tamper-evidence – such ties are not designed to prevent illegitimate tampering. For example, because locking chambers are not designed to be tamperproof they can be manipulated (albeit only intentionally) so that ties can be unfastened and re-closed without the knowledge of the legitimate user.
However, for the likely uses of identification ties this is not a concern because the sealed item does not have intrinsic value; there would not be anything to be gained by tampering with the item. For example, typical uses include bundling or stowing wire cable installations; sealing of waste – including industrial and clinical waste bags; packaging of goods; inspection tagging; industrial equipment and low-value asset tagging. In such applications, the simple design of ties ensures that a solution is provided that is more cost-effective than a more sophisticated security seal.
Where identification is a primary concern of the user, flexibility of tie sizes and printing types also becomes an important consideration. Our range of identification ties are available in many sizes and with different print options – including sequential numbering, printed information, company logos, barcoding and more. For example, our printed cable ties are available in sizes 200x4.8mm, 300x4.8mm and 370x4.8mm to fit the required application. Our printed Tab Ties also offer even greater flexibility, allowing the printing of more detailed information on the tag end of the product, including bespoke barcoding, QR codes and logos as necessary.
If you have any questions about our range of security seals and identification ties, please feel free to give us a call on 01829 760000 or sales@universeal.co.uk to discuss your requirements.