13 Inch Long Brass Mail Slot : measures 3 5/8 inches by 13 inches and this is made for door openings of 2 3/8 inches by 11 inches. Exterior flap is spring:loaded and this comes with a back finish plate. Optional full back flap available. For use on both wood and metal doors. Available in Polished Brass, Antique Brass, Oil Rubbed Bronze, Satin Nickel, Antique Nickel, Black, Paint Black (shown), Chrome, Brushed Chrome and Lifetime PVD Brass. Comes complete with the mounting hardware. For hollow core doors, a mail sleeve is also available (part number DTMS005U32D).