Helps to install the sleeve, add versatility to power drills,good for converting It can convert the original hexagonal to a square head This 3pc Power Extension Socket Adaptor has Hex a bit for all power drill chucks Comes in 3 Sizes: 1/4 inch, 3/8 inch and 1/2 inch for your full range of sockets Suitable for mounting on pneumatic screwdrivers, electric screwdriver, air drill, drill drill, hand screwdrivers etc Specification: Material: Carbide Steel Shank Diameter: 1/4& 39;& 39; (6.35mm) Hex Shank Size: Approx. Head length: 1/4& 39;& 39; Full length: 65mm; Square head side length: 6.35mm Head length: 3/8& 39;& 39; Full length: 65mm; Square head side length: 9.53mm Head length: 1/2& 39;& 39; Full length: 72mm; Square head side length: 12.7mm Package Includes: 3 pieces Socket Bit Adapter Note: The colors may be different for the different display, please understand Please allow 1-3mm error due to manual measurement, make sure you do not mind before you bid