Kryptonite 001706 48' Keeper 712 Integrated Chain Lock Keeper 712 Integrated Chain Lock features 7mm four-sided chain links made from 3t manganese steel Patent-Pending End Link Design secures chain to hardened deadbolt eliminating critical vulnerability and providing extra holding power High security disc-style cylinder is pick and drill resistant; resists most common hand tools Durable weather-resistant nylon sleeve prevents scratches to painted finishes and protects the chain against the elements With a 48-inch (120cm) chain length, the Kryptonite Keeper 712 is a flexible, compact and easy to use deterrent security