The patented sealed optic technology allows removal of heat generated by the lamp without cooling the lamp below proper operating temperature. The built-in 8 in air-cooled flanges have a bead ring to keep ducting securely in place. 95% reflective textured German aluminum interior with 98% reflective corner inserts offer excellent uniformity, output and diffusion. Galvanized steel housing with durable powder coated finish. Manufactured with exacting standards and double neoprene gaskets for an air tight seal. Hinged glass makes changing lamps and cleaning glass easy. Includes tempered glass, built-in socket & 15 ft detachable lamp cord. Will not accept BT37 or larger lamps. US patent: D698987, D698628. US Patent Pending: 29/446133, 29/477993, PCTUS2014014959, 13/533189, 13/945794. Chinese Design patents pending: 201330634881.9, 201330642281.7.