HSS Hole Saw 1. M3/M42 High Speed Bi-metal Edge Welded to Alloy Steel Back for Heavy Duty Cutting ;2, 4/6 variable Teeth ;3, Best Way to Cut Large Hole, Clearing the Chips in Tough Materials ;4, Cutting Depth to 1-1/2"(38mm) and1-7/8"(47mm) ;5, Diameters from 9/16"--8-17/64"(14-210mm) ;6, Can be used in Portable Electric or Pneumatic Tools, Vertical Drill Machines, Lathe, Boring/Milling Machines ...