Bolt seals are high-strength security seals used on shipping containers, railroad and air freight containers. The solid metal core head and a locking cylinder that is encased in shock proof plastic makes for a high level security seal and an efficient tamper deterrent. Solid metal core head makes it impossible to knock seal through latch hardware. It must be removed with bolt cutters, extremely economical, high level security at an affordable price, fits through extremely small slots, cannot be disengaged by intrusion or manipulation. Shock resistant plastic cylinders available in white with laser engraved black lettering. The materials used in the making are carbon steel with zinc finish. Follow the exact procedure for maintain correct installation Insert pin through door catch. Push numbered locking cylinder over end of pin until click is heard. Click indicates that locking ring is activated. Pull on cylinder to ensure that seal is locked properly. Record seal number as required.