22.5 Cu. In. 4" dia. round fixture support box for use with nonmetallic sheathed cable - Machine tapped fixture holes, rigid hard box construction, no distortion with high temperatures, shatter resistant with low temperatures - New work residential construction 2 HR fire resistive walls and ceilings (50 lbs. fixture support) - Fiberglass reinforced polyester - thermoset box with galvanized steel hanger bracket - Size: Depth=2 7/16", Dia=4" - Mount with Nail-on backside HF hanger bracket for adjusting to additional wall/ceiling substrate - Speed Klamps™ factory installed