Kryptonite's Evolution Series 4 1090 Integrated Chain is a 10mm-thick, six-sided link chain made of triple-heat-treated manganese steel for maximum strength that carries a Kryptonite security rating of 8/10. FEATURES: 10mm six-sided chain links made from 3t manganese steel Patent-pending end link design secures chain to hardened deadbolt eliminating critical vulnerability High security disc-style cylinder is pick and drill resistant Patented*, reinforced oval crossbar lock head Sliding dustcover protects and extends cylinder life 3 stainless steel keys – one led lighted key with replaceable battery and 2 new, ergonomic ‘I” keys Durable weather-resistant nylon sleeve prevents scratches Key safe program SPECS: Product dimensions: 35.5” (90cm) chain length Product weight: 6.10 lbs (2.77 kgs)