Steel, heavy-duty, high-security bolt seal for trucks, cargo containers, etc. - wherever high-security and tamper-evidence is required. C-TPAT ISO 17712:2013 Compliant. Meets US Custom and Border container seal requirements. Simple, no-tool application - just click two pieces together to self-lock. Typically, the 23/64" (9mm) diameter shaft is inserted through the hasp of the locking mechanism affixed to door or access point. The 2nd piece of the bolt lock, the locking cap, is then hand-applied, positively clicking in place to lock the bolt.