Greenlee 721-1-1/4P Round Conduit Replacement Punch, 1-1/4-Inch For Slug-Buster Knockout Punches Replacement punch is designed for use with the .492" to 2.52" Slug-Buster Knockout Punches Capacity Mild Steel : 10 Gauge (3.5 mm) Size : 1.701 inch (43.2 mm)