Allied Moulded Speed Klamps™ Round fan box in black color is made of polycarbonate and has injection molded construction. It has saddle mounting. It measures 4.000 Inch diameter x 6 Inch. Fan box has two molded-in speed clamps and has two outlets. It has capacity of 16.5 cubic inches and can be used for fixture support up to 50 lb. Support box is UL listed.