Features Specification The 3pcs screwdriver extension bits are built-have magnetic, for use in hand-held drivers or power drills, to extend all kinds of screwdriver bits. Features: Interface has a locking mechanism, built-have magnetic, automatically pop up batch head. Extend all kinds of screwdriver bits, screwdriver head conversion uses. Fast fastening, greatly improve work efficiency. For use in hand-held drivers or power drills, this 1/4 inch female by 1/4 inch male magnetic bit holder. Helpful to remove or tighten a large number of screws after you've started or loosened them. Suitable for drill, screwdriver, batch head and other to transfer. Has a hardened and tempered steel shaft with a quick-release chuck. Specifications: Material: Chrome Vanadium Steel Color: Black Hex Shank: 6.35mm( 1/4" ) Fir for: 1/4" shank dirver bit Package Weight: 118g / 4.16ounces Package Size: 170 * 50 * 10mm / 6.69 * 1.97 * 0.39in Packing List: 3 * Screwdriver Extension Bits Package List 3 * Screwdriver Extension Bits