Features: Made of high-speed steel, which has good elasticity and wear resistance. High precision, suitable for engraving machine, wood milling machine. The perfect tool for wood. Widely used in boring, milling, drilling, tapping, CNC, carving and other processing operations Large clamping force, wide clamping range, high accuracy. Collet extension or collet or collet extension, other accessories shown in the picture are not included. Specifications: Material: High Speed Steel Bushing Size: approx.31.5x21mm Extension Size: approx.88x28mm/3.46x1.10in Main Color: Silver Optional Types: A, B, C, D Quantity: 1/3pcs Note: Please allow 0-1cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Included: 1 x Extension Or 1 x Collet Or 3pcs/set x Extension Collet Set