" Quick change 1/4" hex shank for all power drills, 1/4" impact drivers and hand screwdrivers. 6", 4" and 2" extensions for better access hard-to-reach fasteners. Built-in magnet, quick release to greatly improve work efficiency. Strong permanent magnets hold the bits in place; accept all 6.35mm hex bits. Hardened tool steel with chrome brackets. Impact resistant tool steel for maximum durability. These bits will stay secure and not break. The sturdy construction allows for a long life of these extensions. Suitable for drill, screwdriver, batch head and others for transfer. A set of essential accessories for electric drills and impact screwdrivers. Extend all types of screwdriver bits, conversion screws; quick attachment; greatly improves work efficiency. "