They are used to cut new threads or repair damaged threads, you will have a smooth tapping experience with them.Description:HSS Co M35 Cobalt Combination Drill Tap Bit M3-M10 Deburr Countersink Drill BitUses HSS-Co material(far better than 4241, 6542 material), more durable,can be used for drilling the steel plate even the 2-4mm 304 steel plate.Service life is 5-10 times longer than tap drill.(Service life will be longer and performance will be better.)118° X Bit Design, you can drill from any angle, no slipping.Package Included:1 x Tap Drill Bit(Just includes the size you choose)Notes:1. Composite taps have high requirements for concentricity, and hand tapping is prohibited.2. Hand drills and rechargeable drills are easy to break, so it is prohibited to use them.3. Dual-purpose models: tapping machine, handheld tapping machine, drilling and tapping dual-purpose machine.