The Master Lock No. 5423D 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 can trust.