Square Boxes are manufactured from durable pre-galvanized steel and are designed to house and protect electrical wiring, switches, receptacles and to support light fixtures. All steel boxes are UL listed and acceptable for use in 2-hour fire rated walls and ceilings. 8-32 cover mounting screws are assembled. Square Box1-1/2 in. DeepWelded with Conduit KO'sRaised Ground600VCombination screw heads provide for faster installationBox may serve as fixture support for fixtures up to 50 lbs.1/2" knock outs