For over 40 years, Kryptonite has been the leader in action sports security. As the creator of the original bicycle u-lock in and the bicycle security category in 1971, Kryptonite has set the standard for premium quality security products. The KryptoLok Series 2 Integrated Chains include 9mm four-sided chain links made from triple heat-treated boron manganese steel. Key Features: 9mm four-sided chain links made from 3t manganese steel. Patent-pending end link design secures chain to hardened deadbolt eliminating critical vulnerability. Hardened deadbolt design provides additional protection. High security disc-style cylinder is pick and drill resistant. Patent pending integrated lock head with \'talon\' deadbolt. Includes 2 new ergonomic \'I\' keys. Durable weather-resistant nylon sleeve prevents scratches. Key Safe Program. Product dimensions: 55cm chain length. Product weight: 1687grams (PBK office scales).