<p>Condition: Type:Step Drill Bit Very , convenient to use Interface has a locking mechanism, built-have magnetic, automatically -up batch head, fast, fastening, greatly improve 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 be self-locked while a drill bit connect to it, grip the black chuck by your one hand and push the hex shank by your another hand, then the connecting drill bit can be pulled out. Rustproof, very , convenient to use. Shank type: hex shank Shank diameter: 6.35mm(1\/4 inch ) Length: 60mm Material: Chrome Vanadium Steel Colour: Silver + Black Quantity: 4 Pcs Package Contents: 4 x Drive Shank Quick Change Bit Drill Chuck Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +\/- 1-3cm.</p>