Greenlee® Knockout SetApplication:Use with manual toolSize:3" Conduit (3.54" or 89.9 mm)Shape:RoundThickness:Punch 10 ga mild steelMaterial:For use in mild steel, brass, copper, aluminum, fiberglass, and plasticsCapacity:Optimized for use in mild steelHole Size:3-1/2 Inch SKU: GRNL.739BB Brand: GREENLEE Country of Manufacture: United States Supplier Part Number: GRNL739BB