The Kryptonite Keeper 585 chain lock features an end pin-link design that secures the chain to a hardened deadbolt and provides extra holding power when subjected to leverage attacks. Feel confident when you lock your bike up, choose Kryptonite. Features: 5mm thick chain links made from hardened carbon steel Hardened locking pin Wafer style cylinder defends against picking and drilling Durable nylon sleeve prevents scratches Includes 2 stainless steel "I" keys Key Safe Program