High security chain tried and tested in the streets of new york. Features 12mm six sided chain links made of 3t hardened manganese steel for maximum strength durable protective nylon cover with hook n loop fasteners to hold in place includes evolution series 4 disc lock with 14mm max performance steel shackle patented oval hardened steel crossbar for extra security hardened double deadbolt locking for extensive holding power high security disc style cylinder with reinforced anti drill anti pull protection system sliding dustcover protects and extends cylinder life 3 stainless steel keys ndash one lighted with high intensity bulb and replaceable battery key safe program awarded 'police preferred specification' status by secured by design the official security initiative owned by the uk police service product dimensions 100cm chain length x 14mm shackle diameter product weight 3.92 kgs patent d564339