5PCS HSS Drill Bit Hole Saw Set 16MM 18MM 20MM 25MM 30MM Openings for stainless steel, iron, aluminum, and various types of pipes. High-speed steel and stainless steel hole saw drill hole saw, sheet metal reamer. Through a special heat treatment, sharp edge, high strength. High precision, smooth cutting, especially impact resistance, wear resistance. Set include 1 each:16MM 18MM 20MM 25MM 30MM