54151-cfbh Ceiling Fan Box, 4 In W, 1-1/2 In D, 4 In H, 4-knockout, Steel, Galvanized

4 in round 1-1/2 in D boxes with new construction bar hangers and side and bottom knockouts are installed in ceiling and walls for mounting heavy fixtures or ceiling fans. Brackets allow the box to be mounted directly onto structural members and provide unobstructed path for the conduit and cable installation.