The ultimate chain for all-round bicycle security, the innovative City chain is built around a nigh-on impenetrable multi layered hardened steel lock body with Powercell technology and the X-plus locking mechanism.Hexagonal section 10 mm hardened steel chain includes a "Powerlink", which fits directly into the lock body for extreme resistance to torque/pulling attack. Lengths quoted are on the external circumference of the whole lock when locked.