Klein Tools 66400 6-in-1 Swaging Punch Swages six sizes of tubing: 3/16-Inch, 1/4-Inch, 5/16-Inch, 3/8-Inch, 1/2-Inch and 5/8-Inch O.D Hex design for ease of extraction Precision machined surface for ease of forming High-alloy steel, heat-treated for strength and durability Suitable for use on copper, aluminum and mild steel tubing