Bolt Seal
A bolt seal is a single-use, high-security tamper-evident locking device made of a hardened metal bolt or pin and a locking body. It secures shipping containers, trailers, railcars, and similar transport units. Once engaged, it must be cut off, and any removal attempt leaves visible evidence of tampering, providing documented chain-of-custody protection.
On the plant floor and in outbound logistics, the bolt seal becomes the last physical control point before a load leaves the building. After a trailer or container is closed, a worker records the unique serial number in the WMS or on the BOL, linking the seal to the shipment. That number travels with the ASN, so receiving can confirm the exact seal is still intact. For raw-material transfers between plants or from supplier to warehouse, the seal reduces pilferage and unauthorized access without adding cycle-count overhead. If the seal number at destination does not match the manifest, the load is flagged as a tamper event and routed to inspection before inventory is booked. This exception workflow protects lot traceability and supports claims. In customs-controlled moves, a high-security bolt seal also satisfies ISO 17712 expectations, making it a routine part of international shipping.
What makes a bolt seal different from a cable seal?
A bolt seal uses a rigid steel bolt and locking barrel, while a cable seal uses a flexible cable. Bolt seals are preferred when rigid, high-security, tamper-evident closure is required for containers and trailers.
What is typically verified at receiving?
The receiver verifies the seal is present, unbroken, and matches the documented serial number. A mismatch indicates a custody exception and usually triggers inspection or a security hold.
Why are bolt seals used for international freight?
They are durable, difficult to remove without bolt cutters, and associated with high-security / ISO 17712-style cargo protection expectations.