10mm six-sided chain links made from 3t manganese steelPatent-pending end link design secures chain to hardened deadbolt eliminating critical vulnerabilityHigh security disc-style cylinder is pick and drill resistantPatented*, reinforced oval crossbar lock headSliding dustcover protects and extends cylinder life3 stainless steel keys – one LED lighted key with replaceable battery and 2 new, ergonomic 'I keysDurable weather-resistant nylon sleeve prevents scratchesKey Safe Program