4 in Round Ceiling Box with two captive mounting nails and four Auto/Clamps. It is constructed of impact-resisitant Noryl thermoplastic, making it virtually unbreakable and non-conductive. Its depth-mounting gauge at bottom of bracket helps you align the box at the proper depth relative to the ceiling. 50 pack.
Auto/Clamp cable clamps molded in, hold wire securly in box.