Features: 1. High quality high speed steel material, strong and durable. 2. Suitable for installation and modification of engraving machine, trimming machine, milling cutter and wood milling engraving head, increasing the use range of fixed engraving head. 3. High precision chuck can improve work efficiency. 4. 3 specifications chuck head can meet different using needs. 5. High precision electric router milling cutter woodworking collet chuck head, can provide you with excellent using effect. Specification: Name: Woodworking cutter chuck Material: high speed steel Application: installation and modification of engraving machine, trimming machine, milling cutter and wood milling engraving head, increasing the use range of fixed engraving head. Size: #1: Port: 10mm, length: 16.5mm, inside size of another port: 8mm, outside size: 11.8mm #2: Port: 10mm, length: 16.5mm, inside size of another port: 6mm, outside size: 11.8mm #3: Port: 10mm, length: 20mm, inside size of another port: 6.35mm, outside size: 12.7mm Package list: 3 x Chuck Head Note: Please allow 1-3mm error due to hand test. thanks for your understanding. Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.