These Annular (Hole) Cutters are made of sturdy M-2 Steel construction, which enables you to cut a burr free hole. It penetrates rapidly, cutting only the periphery of the hole thus allowing the pilot pin to eject the center plug of steel. European Union cutters are Armor Plated. Armor Plated cutters have the following advantages: 3 to 4 times longer tool life before resharpening. Drill with less friction and more power. Withstands higher working temperatures - up to 1480°F (800°C). Dry drilling or lubricating with water simplifies working conditions and cleanup. Prevents cold weld-metal chips do not adhere to the cutter. Ideal for structural steel and hard metal.