The flexibility provided by chain locks are ideal for cyclists who often need to lock their bike up in different locations. The clear advantage of the Chain Lock Steel-O-Chain? 5805K, with its 5mm square chain made from specially hardened steel, is its flexibility. It offers numerous options for locking your bike securely to various objects. Ideal objects include sturdy bike stands or lampposts, as long as the bike does not hinder anyone else when left there.