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. Key lock box enables secure storage of up to five keys; Designed for installation to a wall or fixed object (hardware included).Note: Measure your door's backset, cross bore and thickness to ensure you find the right fit Set your own alpha/numeric combination lock box; Reset the combination for multiple personalized combination code options For indoor and outdoor use; Key safe is constructed with a metal body for durability and weather cover to protect combination buttons Exterior dimensions: 4-5/8 inch (11.7 centimeter) H x 3-1/8 inch (7.9 centimeter) W x 2-1/16 D (5.2 centimeter) Interior dimensions: 3-1/2 inch (8.9 centimeter) H x 2-1/4 inch (5.7 centimeter) W x 1 inch (2.5 centimeter) D; 7.9 cubic inch (20 cubic centimeter) volume