These mirror-polished 3/8" drive premium chromoly hex bits and chrome vanadium socket bit adapters are strong as well as beautiful. The heat-treated bits are precision ground for a tight fit on cap screws and other internal hex fasteners. Use the included adapters to drive the bits with a 1/4" or 3/8" drive ratchet or spinner handle. The set adds a touch of style and utility too, and includes a bit holder tray with a magnetic back. Dependable Powerbuilt bits and adapters meet or exceed ANSI standards and have a lifetime warranty, all at affordable prices.