Won't "walk" or "wander" - 135 Quick-Cut points are self-centering and penetrate quickly with less pressure Metal - For drilling steel, aluminum stainless steel, hard metal and iron. Easier to cut hard metal like stainless steel and cast iron, can also be used for softer materials Heat Resistant - Operates at 1500 RPM or more for maximum efficiency. The straight shank provides a firmer hold and precise centering. For standard drill chucks and ordinary round collet chucks Easy to use and store - 13 pieces of M35 cobalt steel twist drill bits: 1.5mm, 2mm, 2.5mm, 3mm, 3, 2mm, 3.5mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.5mm, 6mm, 6.5mm, 13Pcs Packed in a plastic case for easier use and storage Up to 12 times - M35 cobalt steel, molybdenum and cobalt are added to create a hardened alloy, measuring Rockwell hardness up to 67, for faster cutting and longer life, up to 12 times compared to an average HSS drill