The Kryptonite Keeper 785 is a very strong and durable chain lock made of hardened 7 mm manganese steel links. The surface of the chain is made of nylon and the lock has a vinyl coating to prevent damage to the wheels.Now available in 4 colors (black, gray, red and purple). 7 mm square chain links made of 3T manganese steel. New, more durable DEADBOLT mechanism. High security disc lock body. Package includes 2 ergonomic keys. Waterproof nylon cover protects against scratches. Key Safe program - if keys are lost, send 1st pair of standard replacement keys for free. (Registration required) Dimensions: 85cm chain length Protection level: 5/10 .