Baldwin Package Size Mail Plates. Spring Tension Design, Weatherproof. Made of heavy gauge wrought brass. Overall: 13" x 3.625". Inside Opening: 11.5" x 2.8". Large Opening will accommodate catalogs & small packages. Close fit of flap provides weathertight installation. Bronze spring keeps flap tightly shut & permits vertical installation. A sleeve (0052-324) is available for hollow core doors. 1/box with wood screws. Metal & machine screws & sex bolts are available at an extra charge. Lifetime Polished Brass finish.