General description The Blue Spot Tools 3 Piece Hex Shank HSS Step Drill Set is designed for precision drilling in a variety of materials. This set includes three step drills with a range of sizes, making it ideal for both professional and DIY applications. The high-speed steel (HSS) construction ensures durability and longevity, while the hex shank design provides a secure grip in power tools. Technical specifications Sizes: 4mm, 12mm, 20mm, 25mm, 32mm Material: High-Speed Steel (HSS) Shank type: Hex shank Other information For optimal performance, it is recommended to use cutting oil when drilling to extend the life of the drill bits.