Features 【40CR MATERIAL】: This ER11 collet chuck holder is made of excellent 40Cr material, with high strength and concentricity, which can effectively suppressing vibration. 【QUENCHING PROCESS】: The extension rod with wrench uses carburizing and quenching process, with high hardness and interface fatigue resistance. 【1‑7MM CLAMPING RANGE】: This straight shank tool holder with standard shank diameter and thread, which is suitable for ER11 collet, and the clamping range is 1‑7mm. 【INTEGRATED MOLDING】: The inside and outside of the collet tool holder is integrally formed, with fine processing, the performance is stable. 【FOR MACHINE TOOL】: After inner hole grinding treatment, suitable for high accuracy machine tool processing, with strong practicability, and has a longer life than ordinary tool holders. Specification: Item Type: Extension Rod Product Material: 40Cr + Carbon Steel Hardness: 45-46HRC Head Diameter: Approx. 18mm / 0.7in Clamping Range: Approx. 1-7mm / 0.04-0.28in Adapter Collet: ER11 Thread Type: A Tool Shank Diameter: Approx. 10mm / 0.4in Package List: 1 x Tool Holder 1 x Wrench Note:1. Incorrect assembly may damage the accuracy of the nut and spring2. Only the matching collet chuck can be used to assemble the nut3. Do not clamp tools that exceed the clamping range Package List 1 x Tool Holder 1 x Wrench