17 Cu. In. 4" dia. octagonal fan support box for use with nonmetallic sheathed cable - Machine tapped fixture holes, ground screw, rigid steel construction, New work residential construction 2 HR fire resistive walls and ceilings (70 lbs. fan support and 200 lbs. fixture support) - galvanized steel box with galvanized steel adjustable bar hanger - Size: Depth=1 3/4", Dia=4" - Mount with Adjustable bar hanger - 16" to 24" on center joist application - Steel clamps factory installed