Aluminum alloy case set includes: 8 pieces large drill bits, 9/16”, 5/8”, 11/16”, 3/4”, 13/16”, 7/8”, 15/16”, 1”. Application: Industrial drill bit set for aluminum, copper, maple, brass, steel, oak, MDF, pine, PVC, polycarbonate, acrylic, ABS, nylon and composite materials.Suitable for home DIY, and general building/engineering/woodworking use. Material: Reduced-shank drill bit used M2 high speed steel black and gold, resists corrosion, ensures outstanding durability, sharpness and capability, reduces the friction and runs cooler. Advantage: Black and gold oxide finish,for smoother drilling and is more durable and corrosion resistant.135-degree penetrates hard material and produces small chips to reduce clogging.The split point tip can increase the wear resistance,increases cutting speed with self-centering,clears chips and particles faster. Special Design: 1/2 Inch reduced shank with tri-flatted end locks onto 3-jaw power tools chuck more securely and eliminates slips,allows the bits to fit securely into your power tools and helps eliminate slippage.