Specifications: Standard 3/4" Shank with flats at 90°. Annular (Hole) Cutters enable 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. Cutters are interchangeable with other standard hole-cutting systems. Cobalt steel inverses cutter life and is recommended when drilling stainless steels and other high tensile steels.