WELDED TYPE; WELDED STEEL MATERIAL; 4 INCH; 4 INCH; 1-1/2 INCH; UL APPROVAL; 50 STANDARD PACKAGE; 21 CU INCH CAPACITY; (3) 1/2 INCH BOTTOM ONE END, (2) 3/4 INCH BOTTOM OPPOSITE END, (8) 1/2 INCH SIDE, (4) 3/4 INCH SIDE KNOCKOUT SIZE; 17 KNOCKOUT(S)