Cobalt M35 Material: High cost, but hardness is up to 67, cut faster and has a long life, up to 12 times compared with the average HSS titanium coated bit,Hardened Full Grinding Process: Increases heat resistance and wear well, sharp and durable, used for stainless steel, cast iron, zinc alloy, titanium, aluminum, hard metal, plastic and wood,Sturdy storage case: The case is set up and the bits slide in and out quite easily, the drill bit is securely fastened and won't be rolling around in the bottom of your toolbox making them impossible to find,Rare metric drill bit locally:Metric drill bits are not available at local hardware stores in USA，but when you need metric hole for clearance or tap sizes and drill out broken bolts nuts screws,He can help you,19Pcs Various Sizes:1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7 mm, 7.5mm, 8 mm, 8.5mm, 9 mm, 9.5mm, 10 mm, which covers most your needs,Use Notices: Drill bit should be vertical to the workpiece when used; controling low speed from 200 to 1000 rpm; using cutting fluid will stay cool to make the bit last longer,Widely used: Whether you're a home DIYer or workshoper of professional drilling, it's a great tool