You do not need to use chunk key or pin or wrench,Just a momentary interruption in your work. This item also with the features of low vibration and slowly heating when working,Suitable for grinding, drill, mill and other supporting use. There have got a level mechanism on the handpiece body,It can help you open it quickly and smoothly. This handpiece allow you change out accessories (Such as burs, bits, drills and cutters etc. with) easily. Common used in processing of Jewelry and crafts,Adopting high quality metal material, smooth ,Cabinet and delicate and comfortable using., Manufacturer: Jnchdghwa