Hanperal 12PC Hole Saw Tooth Kit Steel Drill Bit Set Cutter Tool For Metal Wood Alloy (15mm-50mm) 12 PCS Different Size Hole Saw With Hex Key. Gives You Fast, Convenient and steady Cutting. Optimal Rotational Speed:280~300r/min. Cutting Tool for Steel, Wood, Metal, Tiles, Aluminum, Boards etc. Outside Diameter:15mm,16mm,18mm,20mm,21mm,22mm,25mm,26mm,28mm30mm,35mm,50mm.