Set includes --- 4 x 1/4", 2 x 3/8" and 2 x 1/2" drive with 1/4'' hex shaft shank. Two 1/4 (F) to 3/8 inch (M) and 3/8 (F) to 1/2 inch (M) adapters, and two reducers in 3/8 (F) to 1/4 inch drives (M) and 1/2 drive sizes (F) to 3/8" drive (M). Quickly adjust lag bolts and hex head screws. High Quality --- 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 lock ensures a tight fit in the driver's head to prevent slipping in use. Specially machined to fit securely in a hand screwdriver, drill key or impact wrench. The ball bearing ch