- 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 - Durable WEATHER-RESISTANT Nylon Sleeve Prevents Scratches - Key Safe Program - 47.25" (120cm) Chain Length