High Security pull tight seals offer a tamper evident solution for sealing truck trailers, containers, courier bags, doors, drums, and various other cargo holds. Made of polyethylene and a steel locking piece for extra hold these security plastic seals have a breaking strength of up to 55 lbs. and come laser etched with 7 digit sequential numbers. To use simply thread the end of the seal through the closure and into the area marked "enter" at the end of the seal and pull tight. Removable only by bolt or cable cutters.