For use with 2 ½" (6.4 cm) fire dept. valve. Regularly furnished: 22 ga. box; 20 ga. tubular steel door with 20 ga. frame and a continuous steel hinge. All components are powder-coated with an electrostatically-applied, thermally-fused, recoatable white polyester finish. All glass door styles provided with clear tempered safety glass. Wall mounting: semi-recessed. Inside box dimensions: KxLxM: 18x18x8 inches. Minimum wall opening required: 19x19x6½ inches.