Bi-metal hole saws, long lasting, fast cutting and versatile. Up to 2x life in metal cutting. Enhanced tooth geometry, a thin kerf design, and an advanced coating contribute to the efficiency of the cutting process. Easy plug removal. "Speedslot" features a staircase design for easy plug removal. The slot is wider than most and is placed lower on the hole saw with multiple leverage points to easily eject the plug with a standard screwdriver.