Built in self-Release design and tools will never get stuck in holder.Widely used,boring,milling,drilling,silk attack,sculpture,CNC,and other processing.Use with any standard ER collet chucks for coolant-thru tool applications.Each collet is well packed in separate protective container with label.Hardened and precision ground.Performance stability,high accuracy.Durable in use.Name:Extension Rod with ColletColor:black+silverMaterial:40CRPackage Contents:1* C6 EXTENSION ROD7* ER11 spring colletOnly 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.