Vehicle Seals, Bolt Seals, Pull-Tight Seals — Which Do You Need?

Security seals are one of the most misunderstood product categories in Indian logistics and supply chain management. Many businesses use the same type of seal across all applications out of habit — often choosing one that is either under-specified for the risk involved or unnecessarily expensive for a low-security requirement.

This guide explains the five main types of security seals, their specific use cases, and how to choose the right one for your operation.

Why Security Seals Matter More Than Ever

In 2026, cargo theft and tampering continue to cost Indian businesses thousands of crores annually. Regulatory requirements for tamper-evident sealing have also grown more stringent, particularly in pharma, food processing, and cross-border logistics. A correctly specified security seal does three things: it deters opportunistic tampering, provides clear evidence of any breach, and creates a traceable record through unique serial numbering.

Understanding which seal to use is therefore not just a procurement decision — it is a risk management one.

The 5 Main Types of Security Seals

1. Vehicle Seals (Cable Seals)

Vehicle seals consist of a steel cable threaded through a locking mechanism. They are designed for securing truck doors, container hasps, and transit vehicle closures. The cable can be routed through any existing locking point, making them versatile across different vehicle types.

Best for: Truck consignments, interstate transport, container sealing, courier vehicles.

Security level: Medium-high. The steel cable requires cutters to defeat, making casual tampering difficult.

2. Bolt Seals

Bolt seals are the highest security option in the plastic and metal seal category. A hardened steel bolt locks into a metal body and cannot be removed without bolt cutters or an angle grinder. They are used where maximum tamper resistance is required and are widely specified for international shipping containers and high-value cargo.

Best for: Export containers, high-value cargo, customs compliance, ISO 17712 compliant applications.

Security level: High. Often mandated by shipping lines and customs authorities.

3. Pull-Tight Seals (Plastic Strap Seals)

Pull-tight seals work on the same principle as a cable tie — once tightened, the ratchet mechanism prevents loosening without cutting. They are the most economical tamper-evident option and are used in enormous volumes across retail, pharma, food processing, and general logistics.

Best for: Retail bags, medicine packaging, document wallets, general cargo, cash bags, election materials.

Security level: Low-medium. Provides clear evidence of tampering but can be defeated with a sharp blade.

4. Crate Seals

Crate seals are short, rigid plastic seals designed to thread through the locking holes of plastic crates, milk crates, and storage containers. They provide a quick visual indicator that a crate has not been opened during transit without requiring any tools to apply.

Best for: Dairy distribution, beverage crates, returnable packaging, cold chain logistics.

Security level: Low. Primarily a tamper-evidence indicator rather than a security barrier.

5. Meter Seals

Meter seals are specifically designed for utility applications — threading through the inspection cover locking points of electricity, gas, and water meters. They are used by utility companies, contractors, and regulatory bodies to indicate that a meter has not been interfered with since last inspection.

Best for: Electricity distribution companies (DISCOMs), gas utilities, water authorities, AMC contractors.

Security level: Compliance-focused. Designed to meet regulatory requirements rather than resist determined attack.

Comparison at a Glance

Serial Numbering — Why It Matters

All professional-grade security seals are individually numbered, and this numbering is as important as the physical seal itself. A well-run security seal programme records the serial number applied to each consignment at dispatch and verifies it at delivery. This creates an auditable chain of custody that is admissible as evidence in case of a dispute or insurance claim.

When purchasing seals, always verify that the numbering is laser-etched or permanently printed rather than simply stickered — adhesive labels can be removed and transferred to a replacement seal, defeating the purpose entirely.