22.5 Cu. In. 4" dia. round fixture support box for use with nonmetallic sheathed cable - Machine tapped fixture holes, ground strap, 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 adjustable bar hanger - Size: Depth=2 7/16", Dia=4" - Mount with Adjustable bar hanger - 16" to 24" on center joist application - Speed KlampsÖ factory installed