The Performance Tool interchangeable bit socket system is the perfect tool for tackling a variety of projects. With sixteen tamper-resistant star bits sizes included, you'll have everything you need for even the toughest tasks. Built to last, our socket system is made with chrome vanadium alloy steel construction for strength and durability. The polished nickel chrome plated bit holders resist corrosion and are heat-treated for added durability, making them the perfect tool for long-term use. Plus, with a bonus storage rail included, everything can be kept concisely organized, making it easy to find the right bit for the job at hand. This set includes 3/8 drive x 1/4 inch & 3/8 drive by 5/16 inch hex adapters, as well as a range of 1/4 inch and 5/16 inch hex bit sizes, including T6, T7, T8, T10 (2), T15 (2), T20 (2), T25, T27, T30, T40, T45, T50, and T55.