Multi-function- Used in the installation of pneumatic screwdriver, electric screwdriver, pneumatic drill, manual screwdriver and other installation for the hex tool. It is a good accessory for conversion. for universal socket, impact adapter and reducer kit, universal joint kit, socket adapter and reducer kit, Drive socket extension bar kit, Drive collision socket kit. Colorful Design- Different color rings make it easy to select the right one. The brand has a replacement guarantee. Please contact us for a replacement if there is any issue or problem. PACKAGE CONTAINS- 3Pcs: 1/4", 3/8", 1/2" each with 1/4" hex bit fits any quick change drill chuck system. Turns any drill into a power nut Heavy-duty spring-loaded ball bearing holds sockets securely in place. Snap-on socket tight and won't slip. Usage- A great tool for any toolbox set. This 3 Hex Driver Extension Bar Set is designed to meet a variety of needs. Fits perfectly into the chuck or manual screwdriver. Comprised of your most common 1/4", 3/8" and 1/3" drill bit sizes. Variable sizes. Offers versatility and convenience no matter which tool you have chosen to use. Material - High quality 6150 CR-V Chrome vanadium steel construction and heat treatment for high hardness and good toughness; sandblasted surface for better fatigue resistance. Size: 1/4*1/4*65mm long - 1/4" shank can be converted to 6.35mm square head Length 3/8*1/4*65mm - 1/4" shank can be converted to 9mm square head 1/2*1/ 4*72mm length - 1/4" shank can be converted to 13mm square head