Allied Moulded fiberglassBOX 4 In. Nail On Vapor Barrier Ceiling Fan Box

4-inch diameter side nail mount fan and fixture box. Fiberglass construction with a flexible polyurethane flange to form an energy efficient vapor seal. Does not distort with high temperatures, shatter resistant with low temperatures. Can help stop warm and cool air leaks. 35-pound fan rated, 50-pound fixture rated. 1/2-inch offset. UL (Underwriter's Laboratories) listed. 4 In. W. x 2-3/8 In. D.