Set contains a range of the most popular screwdriver and nut-driver sizes for use in wood, plastic and metal. Professional quality set is manufactured using high-speed steel with precision 135-degree split-point tips to help prevent walking. Proprietary heat treatment makes for sharper, longer-lasting life. Black oxide coating resists corrosion. Ultra-Lok 1/4" hex shanks reduce the risk of bit spin-out. Pro-grade, maximum magnetic 3" bit holder and nut-drivers provide extra-strong fastener retention. Compatible with all quick-change connector systems, 3/8" or 1/2" electric or battery-powered drill/drivers, and 1/4" impact drivers.