Knockout Punch Set, 3/4-Inch - 53727SEN | Klein Tools
AMZCNC Hydraulic Knockout Hole Punch Driver Kit 1/2 to 4 inch Electrical Conduit Hole Cutter Set KO Tool Kit Metal Sheet Puncher (12TON(1/2"~4")) : Amazon.ca: Tools & Home Improvement
Greenlee 745H-4 Knockout Punch Unit for 4 Inch Conduit : Amazon.ca: Tools & Home Improvement