Ideal for mounting above entryways and loading docks. Construction: Rugged, corrosion-resistant die-cast aluminum back housing and hinged door frame. Castings are sealed with a one-piece gasket to inhibit the entrance of external contaminants. Finish is bronze polyester powder paint for lasting durability. Electrical: Ballast is constant wattage autotransformer. Ballast is 100% factory-tested. Metal halide: super CWA pulse start ballasts, 88% efficient and EISA compliant, are required for 250-400W (must order SCWA option) for US shipments only. CSA required for pulse start shipments to Canada. 250M and 400M do not comply with California Title 20 regulations. Socket: Mogul-base socket, nickel-plated screw shell and center contact. Optics: Refractor is prismatic borosilicate glass. Reflector is die-formed anodized stippled aluminum. Mogul-base lamp included in carton. Installation: Housing is configured for mounting directly over a standard 4 outlet box or for surface wiring via any of three convenient 1/2 threaded conduit entry hubs. Listing: UL Listed to US and Canadian safety standards. Suitable for wet locations (250C maximum ambient temperature).