Drawn steel construction with "J" bracket with spurs, slotted holes for toe-nailing and gauging notches at 3/8 in and 1/2 in. and nonmetallic sheathed cable clamps. 4 in. x 1-1/2 in. deep. Supplied with three 1/2 in. knockouts. Combination Phillips/slotted screw heads. 15.5 cu. in. capacity.