Since it is a tapered circuit board, work can be conducted in flat surface without engraving even if the work angle is high.Since the outer circumference and inner side of the polished surface will wear at the same time, it is excellent in durability and can be used until the end.Metal black layer removal, bead removal on welding masks.Grinding and polishing of difficult-to-cut material such as stainless steel.Grain Size (#):40Outer Diameter x Blade Length x Hole Diameter (mm):180 x 20 x 22Max Working Rotation Speed (rpm):8400Blade Number (sheet):90Working Angle: 15 to 25Maximum working peripheral velocity: GPK10016Z: 72m/s(4300m/min)GPK18022Z: 80m/s(4800m/min)Only ?3100mm adapter for 15mm hole 10 pieces per box (sold separately 5 pieces: GPTAS-5P)