Pass and Seymour Thermoplastic Molded 4 In. Round Ceiling Box with Adjustable Bracket

4-inch round ceiling box with a bar hanger that adjusts to 16-inch or 24-inch joist spacing. It has four auto clamps. It is constructed with impact-resistant Noryl thermoplastic, making it virtually unbreakable and non-conductive. Features a depth-mounting gauge at bottom of bracket helps you align the box at the proper depth relative to the ceiling. UL (Underwriter's Laboratories) listed for fan and fixture support.