The Master Lock 5423EC Wall Mount Push Button Lock Box features a 3-1/8in (79mm) wide metal body for durability. The wall mount design offers permanent installation. Set your own 4 character combination for keyless convenience and increased security. The protective weather cover prevents freezing and jamming; And molded bumper and vinyl coated shackle prevent scratching. The Limited Lifetime Warranty provides peace of mind from a brand you know and can trust.