This motor shaft collet is made of high quality steel material, straight with clamping nut to be tightened.Extension rod diameter and the other parts are precision ground to eliminate unbalance, increase safety when cutting.Straight extended fits for deep processing, meeting the needs of extending the depth of processing. Collet is packed in a protective container with label for safe transportation and storage.It is widely used in boring, milling, drilling, tapping, grinding and other processing.This collet is made of high quality steel for milling lathe tool and work-holding engraving machine. ER straight rod type collet extension handle body is relatively long, suitable for deep hole processing. The nut can be directly tightened to a clamping force. This collet can reduce costs, efficiency and would be a good replacement part for your old one.Type: ER11A-8mmColor: black,silverMaterial: 45 SteelHeight: 40mm / 1.57 inchShaft Diameter: 16mm / 0.63 inchShaft Inner Diameter: 8mm(+/-0.02mm) / 0.31 inchNut Diameter: 19mm / 7.48 inchNut Inner Diameter: 9mm / 3.54 inchPackage included: 1 X ER22 A-8mm Motor shaft tool holderOnly the above package content, other are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.