Set includes --- 4 x 1/4", 2 x 3/8" and 2 x 1/2" drive with 1/4'' hex shaft shank. Two 1/2" adapters 4 (F) to 3/8 inch (M) and 3/8 (F) to 1/2 inch (M), and two reducers in the 3/8 (F) to 1/4 inch (M) and 1 /2 drive sizes (F) to 3/8" drive (M). Quickly adjust lag bolts and hex head screws. High Quality --- The extension adapters are made of heat treated chrome vanadium steel with a black oxide coating. Adapters and reducers are made of high-strength premium chrome steel with a manganese phosphate coating to help resist rust and corrosion and ensure a lifetime of use. Usage General use --- This Hex Shank Screwdriver Extension Bar Set is designed to meet a variety of needs. Fits perfectly into the chuck or manual screwdriver. Comprised of your most common drill bit sizes of 1/4", 3/8" and 1/2", varying sizes for shanks. Provides versatility and convenience no matter which tool you choose to use .Ideal for DIY, household maintenance and general r Purpose --- This adapter set is designed to provide a securely locked extension to your existing tool Provides extra length to access a multitude of hard-to-reach spaces Spring-loaded ball latch ensures a tight fit in the driver's head to prevent slipping during use Specially machined to fit securely in a hand screwdriver, drill wrench or an impact wrench.The ball bearing ch After-Sales Service --- We will provide you with the friendliest customer service.Welcome to contact us If you have any problems with your extension extension kit and disk jack adapter EU, just contact customer service for help, parts, replacement or refund-6