Kryptonite Keeper 585 Integrated Chain Lock - 85cm (2.8"), 5mm, Keyed - This 5mm chain lock features end pin-link design secures the chain to hardened deadbolt and provides extra holding power when subjected to leverage attacks. 5mm, 4-sided chain links made of 3t manganese steelIncludes 2 standard, stainless steel "I" keysHigh security disc-style cylinder is pick and drill resistantKey Safe Program