This Die Grinder and stones kit set is intended for the professional use of polishing,smoothening, de-burring and sharpenning . The 1/4" (6mm diameter, 25 mm shaft) and 1/8" (3 mm diameter, 25 mm shaft) stones are used for grinding. With its multi-functioning features, our product can be used for hobby, automotive and construction jobs. The whole device is very easy to handle; thanks to its ergonomic design, light weight housing, low vibration and variable speed control. Delivering includes 10 x interchangeable grinding stones with 1 air die grinder, 2 mounting keys, 2 collets and 1 storage case.