The internal cooling through hole and central through hole design support water cooling. Anti-vibration and enhanced resistance to bending help reduce the need for long cutting tools. Advanced vacuum quenching technology enables carbon and oxygen co-permeation, increasing tool shaft hardness and extending service life. Hex nut allows for easy clamping and secure tool holding, offering high rigidity and strong clamping force. UM-type ER extension rod features a tight fit with fine teeth; the ER chuck and nut sizes vary based on specifications. Helps reduce the use of extended tools, lowering costs and improving machining efficiency. Outer diameter of the extension rod and related components are precision ground to minimize imbalance and improve cutting stability. 1 x Collet Chuck Holder Item Type: Collet Chuck Holder Model: SL25-ER20-80 Material: High Speed Steel Purpose: For use with lathes and various machining centers Shank Diameter: Approx. 25mm / 1in Handle Length: Approx. 80mm / 3.1in Adapter Chuck: Approx. 25mm / 1in Scope of Application: CNC lathe, milling machine, drilling machine