HGC904425 Completely sealed featuring hinged glass and double gasket (between glass and reflector and glass and frame) for an air-tight seal. Includes tempered glass, built-in socket and 15 ft lamp cord. Highly reflective aluminum interior for excellent reflectivity and diffusion. Swing Stop retention cable keeps glass from abruptly swinging down. Captured thumb screws and closure mechanism for ease of use and excellent sealing. Air-cooling flanges have a bead ring to keep ducting securely in place. Powder-coated galvanized steel housing. US Patents: D698,628, D543,652, D545,485.