This heavy duty bike lock features a patented deadbolt system, and index design, making it easy to rotate and reset your combination. A patented end link design that securely connects the chain to a hardened deadbolt inside the lock, eliminating weak points. Made from 9.5mm hardened steel with four-sided links, this bike lock provides excellent resistance against cutting and leverage attacks. Kryptolok 990 Combo Chain extends up to 90cm (35.4 in) in circumference.