The BlueSpot 15 Pce Grinder Set is ideal for grinding and polishing a range of materials. The set contains: 1x mini air die grinder, 2 x hand wrenches, 1 x 3mm(1/8") collet, 5 x 1/4"(6mm) shank grinding stones, 5 x 3/8"(3mm) shank grinding stones, 1 x nipple. Free speed 25,000RPM. 4 CFM (114L/min) air consumption. 90PSI (6.2 bar) Operating Pressure. 1/4" BSP Inlet. The set is supplied in a useful, blow molded, plastic carry case.