Blades have a tungsten carbide tip for longer life. Cuts sheetrock, MDF, plaster, plywood, fiberglass, Hardi board (does NOT CUT through Cement or Concrete). Used with the Hole Pro Professional models: X-148, X-230, X-230+, X-305, X-425, Adjustable Hole Cutters. ***DO NOT FIT THE HOLE PRO MODEL T-200***