18mm hardened MAX-Performance steel shacklePatent-pending hardened double deadbolt design gives additional protection against twist and cut attacksPatented steel sleeve over cross bar for double security Highest security disc-style cylinder is pick and drill resistant Sliding dustcover to protect from dirt and debris 3 stainless steel keys, including new design and one LED replaceable key fob Key Safe Program Protective vinyl coating Dimensions: 3.25INX6IN