Edge Impact Tough Hole Saws deliver 2X life over standard impact-rated hole saws, for dependability and value. These tough hole saws feature 8-TPI Bi-Metal teeth, for clean fast cuts in sheet metal. They are engineered for fast performance in today's high-torque impact drivers. Each hole saw has an impact-rated 1/4 In. hex shank for use in impactors and most drills. It features a depth stop to help prevent breakthrough for more precise drilling, as well as a pilot bit spring for automatic plug ejection. The integrated one-piece design means that no separate arbour or pilot bit is required