Kryptonite Evolution Series-4 1016 Integrated Chain Bicycle Lock Bike Lock (5.25") 10mm six-sided chain links made from3T MANGANESE STEEL Patent-pendingEND LINK DESIGNsecures chain to hardened deadbolt eliminating critical vulnerability HIGH SECURITY DISC-STYLE CYLINDERis pick and drill resistant Patented, reinforcedOVAL CROSSBAR LOCK HEAD SLIDING DUSTCOVERprotects and extends cylinder life 3 STAINLESS STEEL KEYS one LED lighted key with replaceable battery and 2 new, ergonomic I keys DurableWEATHER-RESISTANTnylon sleeve prevents scratches Key Safe Program Product dimensions: 5.25 (160cm) chain length Product weight: 9.70 lbs (4.40 kgs) 10mm six-sided chain links made from 3t manganese steel Patent-pending end link design secures chain to hardened deadbolt eliminating critical vulnerability High security disc-style cylinder is pick and drill resistant Patented, reinforced oval crossbar lock head Sliding dustcover protects and extends cylinder life 3 stainless steel keys  one LED lighted key with replaceable battery and 2 new, ergonomic I keys Durable weather-resistant nylon sleeve prevents scratches Key Safe Program