Condition: New Type:Step Drill Bit Very durable, convenient to Interface has a locking mechanism, -have magnetic, automatically pop up batch head, fast, fastening, greatly work efficiency. Suitable for drill, screwdriver, batch head and other to transfer Extend all kinds of screwdriver bits, screwdriver head conversion uses Suitable for electric drill, screwdriver, wind batch transfer using to play the role of releasing bit holder The interface has a locking function: it will be -locked while a drill bit to it, grip the black chuck by your one hand and push the hex by your another hand, then the connecting drill bit can be pulled out. Rustproof, very durable, convenient to . type: hex diameter: 6.35mm(1/4 inch ) Length: 60mm Material: Chrome Vanadium Steel Colour: Silver + Black : 1 Pcs Package Contents: 1 x Drive Quick Change Bit Drill Chuck Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.