You do not need to use chunk key or pin or wrench. Just a momentary interruption in your work. There have got a level mechanism on the handpiece body. It can help you open it quickly and smoothly.This item also with the features of low vibration and slowly heating when working.Suitable for grinding, drill, mill and other supporting use, Adopting high quality metal material, smooth surface.Cabinet and delicate and comfortable using.Common used in processing of Jewelry and crafts.Colour: silver + blackMaterial: metalLength: 14.2 cmCollet : 2.35 mmPackage Contents:1 * Flex Shaft MachineOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.