DOUBLE REINFORCED CONSTRUCTION WITH STAINLESS STEEL OUTER CASE AND COLD ROLLED STEEL INNER CASE FOR STRENGTH AND DURABILITY. 3/4"" THICK NICKEL PLATED HARDENED STEEL SHACKLE RESISTS RUST. EASY DEPENDABLE 3-NUMBER DIALING WITH AUTOMATIC SCRAMBLING FEATURE TO PREVENT REOPENING OF LOCK. STANDARD BLACK DIAL. ALL MASTER LOCK LOCKS ARE NOT RETURNABLE.