Fixed length seals are often seen as a simple product. Click it in, note the number, done. That thinking is understandable, and at the same time the biggest pitfall when choosing the right seal. In practice, it's more nuanced. Not because fixed length seals are complex, but because the application varies. And that's exactly why no single type is always the right choice.
The application determines the properties
A fixed length seal always has the same purpose: making it visible whether unauthorised access has occurred. How that happens differs per situation. Think about:
who applies and removes the seal
whether manual emergency opening is required
how much force the seal is exposed to during use
how and where it gets inspected
In practice, we regularly see fixed length seals chosen out of habit, or purely based on breaking strength. A metal seal was once used at a location where staff needed to open it by hand immediately in an emergency. What was meant as extra security worked against them in that situation. The reverse also happens: light plastic seals get used on truck doors where the closure regularly comes under tension. The result: unwanted breakage and discussions afterwards.
A fixed length seal isn't a standalone product. It's part of a process. Those factors determine whether a light plastic seal is enough, or whether a metal version fits better.
NSS560-L Seal
Tyden Ball Seal
Metal Flat End Seal Guard Lock
When manual breaking is required
In situations where speed and ease of use matter, plastic fixed length seals with a lower breaking strength are often the choice. These break easily by hand and make inspection fast and clear. The NSS560-L Seal falls into this category. Thanks to its extra length and printed flag, the imprint is easy to read at a glance. This makes the NSS560-L well suited to TIR lines, where inspection often happens quickly and from a distance.
Stronger, but still flexible
Sometimes a higher breaking strength is needed, without switching straight to metal. Think of sealing truck doors, empty containers or rail wagons. The Plastic Truck Seal is the answer here. With a breaking strength of 28 kg, it's the strongest plastic fixed length seal in the Navacqs range. The fixed length always leaves some play, while the wider band and acetal insert offer extra resistance against unwanted breakage. Sealing still happens by hand. Opening doesn't.
And the maximum threshold
In situations where extra certainty is needed, metal fixed length seals are the choice. These can't be broken by hand and always require tools. That raises the physical barrier against unauthorised opening. The Tyden Ball Seal is a well-known example. With a breaking strength of around 52 kg and customs approval, this seal is widely used within European transport. Its signature ball-click mechanism has been around for decades and is known for its reliability.
Anyone looking for a metal seal without needing customs approval can choose the Metal Flat End Seal Guard Lock. This version offers a breaking strength of around 45 kg and is a cost-effective alternative. Its patented locking mechanism makes tampering visible and reuse impossible.
No 'best' fixed length seal, just the right choice
Every fixed length seal in the Navacqs range shares the same basic principles:
fixed length
visible breakage
unique imprint and sequential numbering
The difference isn't better or worse. It's risk profile and working method. A light plastic seal is designed for quick visual inspection. A metal version raises the physical barrier. Both do exactly what they're meant to, as long as they're used in the right place. It's precisely because several types exist that you can make a considered choice per application.
In short
Anyone who sees fixed length seals as a standard product misses the distinction that makes the real difference in practice. Matching breaking strength, material and version to the work process prevents discussions, delays and false security. Want to think through which fixed length seal fits your application best? Feel free to contact our team. We're happy to think it through with you.
