Security Seals and Tamper-Evident Systems: a Practical Guide

Author: Marco Ghirardi – StickersLab S.r.l.
Last updated: 13 July 2026

Security seals and tamper-evident systems make an unauthorised opening, removal or access visible. They can be used by private individuals, shops, laboratories, workshops, companies, warehouses, logistics operators, e-commerce businesses, property managers and facility operators.

The right choice depends on what you need to protect: a parcel, a box, a briefcase, an electronic device, a technical door, a meter, a document or a shipping container each require different solutions.

Quick choice

For parcels and cartons choose VOID tape or a security bag; for warranties and devices use VOID or ultra-destructible labels; for sacks, cabinets and containers choose plastic seals; for doors, valves and technical openings consider cable seals; for shipping containers and critical transport you may need bolt seals with ISO 17712 documentation.

What does tamper-evident really mean?

An anti-tampering system, also called tamper-evident, does not necessarily make opening impossible. Its main purpose is to deter, identify or document an access attempt.

Deterrence

The presence of a seal makes it clear that the contents or the device are under control.

Evidence of opening

Breakage, the VOID message, detachment or fragmentation make it possible to detect that the system is no longer intact.

Identification and traceability

Sequential numbering, barcodes, QR codes and internal records can link the seal to an order, a parcel, a vehicle, a piece of equipment or an operator.

Important

A tamper-evident seal does not replace a lock, an anti-theft device, an alarm system or a surveillance procedure. It should be considered a passive control measure, not an absolute guarantee against theft or unauthorised access.

Which solution should you choose for each application?

Application Indicative solution What to check
E-commerce cartons and parcels VOID tape or closure label Adhesion to the carton, width, visible message and quantity
Documents, keys and sensitive items Numbered or barcoded security bag Size, closure, receipt, numbering and opacity
Notebooks, smartphones, equipment and warranties VOID or ultra-destructible label Surface, desired residue, size and temperature
Sacks, boxes, cabinets, trolleys and containers Adjustable or fixed-length plastic seal Usable length, hole diameter, strength and numbering
Doors, valves, cages, tanks and technical openings Cable seal Cable diameter and length, material and removal tool
Containers and international transport Bolt seal ISO 17712 documentation, numbering and carrier procedures
Water, gas and electricity meters Sealing wire, technical seal or magnetic indicator Compatibility with the installation, environment and inspection procedure

The main types of seals and tamper-evident systems

1. Plastic seals

They are among the most versatile solutions for sacks, containers, lockers, trolleys, briefcases, cash boxes and shipments. They can be adjustable, also known as pull-tight, or fixed-length.

Adjustable models can be tightened to the desired position. Fixed-length models help standardise application. Sequential numbering and different colours make checks, inventory and recognition easier.

See plastic seals

2. Cable seals

They use a metal cable passed through one or more closing points. They are suitable for doors, valves, cages, tanks, vehicles, technical containers and applications where an ordinary plastic seal is not strong enough.

Before choosing, check the cable diameter and length, the size of the hole, the required strength and the removal method. The most robust models may require cable cutters or a suitable tool.

See cable seals

3. Bolt seals for containers

Bolt seals, also called pin or bar seals, usually consist of a pin and a single-use locking body. They are used mainly on containers, trailers and logistics closures that require a stronger mechanical barrier.

When a procedure requires compliance with ISO 17712, it is not enough for the product to look like a bolt seal: you need to check that the specific model comes with the required documentation.

See bolt seals

4. VOID labels and tapes

When removed, they reveal a visible message or pattern, such as VOID, OPENED or a security pattern. They are suitable for boxes, devices, doors, containers, documents, equipment and packaging.

Some versions transfer the message completely onto the surface, others transfer it only partially, and some leave no residue on the surface. The choice depends on how evident the removal needs to be and whether the substrate must stay clean.

To learn more about this technology specifically, read the guide to tamper-evident labels .

See VOID labels and tapes

5. Ultra-destructible labels

They are made from materials designed to break into small fragments when someone tries to remove them. This makes it difficult to peel the label off intact and reuse it on another object.

They are often used as warranty seals, for equipment identification and component control, and to protect screws, hatches or access points.

See ultra-destructible labels

6. Security bags

They are suitable for documents, keys, valuables, samples, returns, confidential mail and small items. They may include a VOID closure, sequential numbering, a barcode, a writable area and a tear-off receipt.

For business use it is important to choose the right size and to define who prepares the bag, who records the number, who receives it and how any anomaly is handled.

See security bags

7. Tamper-evident systems for meters

Meters, valves, boxes and measuring devices may require sealing wire, twist seals, protective covers or specific magnetic interference indicators.

These are technical applications: the product must be chosen according to the type of installation, the environment, the procedure of the utility or property manager and the planned inspection method.

See meter systems

Water, impact and tilt indicators: what is the difference?

A condition indicator does not do exactly the same job as an opening seal. It detects a specific event, for example contact with a liquid, an impact or tilting beyond a set limit.

  • Water indicators can signal contact with liquids on devices, components or equipment.
  • Impact indicators help check whether a parcel has suffered a shock during transport.
  • Tilt indicators can show that a package has been turned over or handled in an unintended way.

These devices can complement a tamper-evident closure, but they should not be confused with a mechanical seal or a VOID closure.

Solutions for private individuals

Private individuals can also use tamper-evident seals and stickers when they want to check the integrity of an object or a closure without installing complex systems.

  • Parcels, boxes and returns to be shipped.
  • Briefcases, lockers, cash boxes and small containers.
  • Notebooks, consoles, smartphones and devices sent for repair.
  • Sports equipment, tools, spare parts and items to be identified.
  • Documents, keys or small items stored in numbered bags.

For private use, a simple, immediately readable solution is often more useful than an overly robust or complex device.

Solutions for companies, logistics and e-commerce

In a company, a seal should not be treated as a simple product to apply: it must become part of a repeatable procedure. Numbering or barcodes are only valuable if they are recorded and checked.

An effective business process may include:

  1. Assigning the seal to an order, parcel, vehicle or piece of equipment.
  2. Recording the serial number or barcode.
  3. Application by an identified operator.
  4. Where appropriate, a photo of the seal and the closing point.
  5. Checking the number and integrity on delivery or inspection.
  6. Reporting differences, breakages or anomalies.
  7. Storing the data according to internal procedures.

This organisation is particularly useful for logistics, e-commerce returns, maintenance, asset control, laboratories, IT, document transport, public administration, residential buildings and the management of technical equipment.

How to choose the right seal

1. Identify the closing point

Check the hole diameter, the distance between the points to be connected, the available space and any edges that could damage the seal.

2. Check the surface

For stickers and tapes you need to distinguish between cardboard, plastic, metal, glass and painted, rough or porous surfaces. A solution that works on smooth metal may adhere poorly to recycled cardboard or low-surface-energy plastics.

3. Consider the environment

Temperature, humidity, UV rays, water, dust, vibration and outdoor exposure can affect adhesion and durability.

4. Decide what evidence you want

You can choose mechanical breakage, a VOID message, residue on the surface, fragmentation of the label or a number to compare.

5. Consider removal

A robust seal may require tools. A label that leaves residue may be right for packaging but unsuitable for a delicate surface or a device that must stay clean.

6. Define quantity and customisation

For business supplies, consider annual quantity, reorder frequency, colours, numbering, barcodes, logo and size. Customisation and minimum production quantities depend on the chosen model.

Bolt seals and ISO 17712

ISO 17712:2013 sets out uniform procedures for the classification, acceptance and withdrawal of acceptance of mechanical seals used on freight containers.

The standard does not mean that any metal or bolt seal is automatically compliant. When compliance is required by a customer, a freight forwarder or an international procedure, you need to check the documentation for the specific model, not just its commercial name.

Even the best seal loses its effectiveness if it is stored without control, applied incorrectly, recorded with the wrong number or accepted on delivery without checking that it matches.

Mistakes to avoid

  • Choosing the strongest seal without checking whether it fits through the available hole.
  • Applying a label over dust, grease, silicone, moisture or an incompatible surface.
  • Using a no-residue label when you actually want to leave a permanent trace.
  • Recording a shipment without noting the seal number.
  • Not establishing who is authorised to break or replace the seal.
  • Describing a product as “ISO 17712” without checking the model’s documentation.
  • Presenting a seal as an absolute guarantee against theft or tampering.

Frequently asked questions

Does a seal really prevent theft?

Not necessarily. It can deter, make access more difficult or show that a closure has been breached, but it does not replace an anti-theft system.

What is the difference between VOID labels with and without residue?

The transfer version leaves a message or pattern on the surface. The no-residue version shows the opening on the label but tends to keep the substrate cleaner. The exact characteristics must be checked on the product page.

Can seals be reused?

Most security seals are single-use. After breaking or removal they must be replaced with a new seal, ideally recording the new number.

Which solution is best for a parcel?

On an ordinary carton, VOID tape or a label applied over the opening point may be suitable. For documents or small sensitive items, a security bag may be more appropriate.

Which label should I use on an electronic device?

It depends on the surface material and the desired effect. VOID labels are useful when you want an opening message to appear; ultra-destructible labels when you want to make intact removal difficult.

Are all bolt seals ISO 17712 compliant?

No. Compliance must refer to the specific model and be supported by the relevant documentation.

Can I order customised seals?

Numbering, colours, logo, text, barcodes or custom sizes may be available on certain models. Feasibility and minimum quantity depend on the product and the production process.

Find the right tamper-evident system

Browse the full range or go straight to the category closest to your application.

Supplies for companies

For quantities, recurring supplies, numbering, barcodes, colours, sizes or customisation, you can send a request stating the application, surface, environment, expected quantity and desired result.

For a more accurate assessment, it also helps to attach a photo of the closing point or of the surface the product will be applied to.

Request a business supply

Technical reference

This guide is for information only. Performance, compliance, strength, compatibility and methods of use must be checked on the product page and in the documentation of the specific product.