Built in self-Release design and tools will never stuck in holder. Use with any standard ER collet chucks for coolant-thru tool applications. Each collet is packed in separate protective container with . Hardened and precision ground. Performance stability, high accuracy. Durable in use. Widely used, boring, milling, drilling, silk attack, sculpture, , and other processing. Colour: black + silver Material: 40CR Size: Spring Collet: 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, Extension Rod: C20-ER16A-32L-10MM Package Contents: 10 * ER16 Spring Collet 1 * Extension Rod Only 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 . The measurement allowed is +/- 1-3cm.