MIBRO’s bi-metal hole saws are manufactured with a heavy-duty backing plate for superior rigidity. M3 high-speed steel heat-treated teeth are electron beam welded to the blade body for strength and consistent blade hardness. 4/6 variable tooth pitch gives efficient and safe cutting of metal, plastic, and wood. EZE Slot is designed for quick and easy plug removal on all blades with a diameter of 1 3/4 in (45 mm) and larger. Hole saw includes screw in mandrel and pilot drill.