Gardner Bender 4-point knockout punches and dies are designed to punch clean, round holes through 10 gauge mild steel, 12 gauge stainless steel or other soft metals up to 0.135 inch in thickness. Punches and dies are interchangeable, in any combination, with most brands of knockouts. This kit includes punch, die and drive screw to punch a hole diameter sufficient for 3/4 inch diameter pipe / conduit, actual hole diameter is 1.086 inch additional sizes available to specifically permit fast and easy installation of electrical conduit and pipe of nominal sizes 1/2 inch through 4 inch, in all commonly available increments.