High security chain, tried and tested in the streets of New York. 12mm six-sided hexagonal chain links made from triple heat-treated boron manganese steel for ultimate strength, including a larger cinch ring. Prevent leverage attacks. EV series 4 Disc lock has flat keyway locking mechanism for extensive holding power and high picking resistance and an ovalised, extra-strong crossbar to withstand pull force and cut force. 14mm hardened steel shackle. Sliding dustcover.