The Kryptonite Keeper 85cm Chain Lock is lightweight with an integrated chain made from hardened triple heat treated boron manganese steel with 7mm four sided links, secured together with an integrated lock head & pin-link design to secure the chain to the hardened deadbolt. To protect your bikes paintwork from knocks & scratches, the chain links are enclosed in a nylon webbing sleeve. High security disc-style cylinder is pick & drill resistant