Handheld aku die grinder 3.6 Li-ion 1300mAh with USB charging is a great tool not only for grinding crystal jewellery. Thanks to rubber handles, it doesn’t slip from your grip and it suppresses vibrations. You can use it for polishing, milling, grinding, drilling holes and other tasks as well. The biggest advantage is that you can charge it using a USB port and that a special Li-ion battery lasts up to 40 minutes and you can charge it on the fly. Thanks to its size you can work with it virtually anywhere. Shaft size is 3.2 mm.