Diamond drill bit: made of carbon steel with diamond coating for porcelain, glass, marble, ceramics, rock and granite, etc. High quality hole drilling: blade thick with a brazed design for long life, ideal for drilling clean, precise holes and cutting perfect circles Long life: heavy-duty hole saws provide superior performance, durability is more 8 times than other common diamond hole saws Attention: Start drilling at a 45 degree angle, and drill vertically when the crescent-shaped edge is cut to prevent the hole saw from slipping. Never let your drill bit dry out and use water to keep it moist and cool. How we're different: We aim to make the best products to inspire our customers to live a healthier lifestyle. convenient and safe. We have a professional product monitoring team who focus on every detail that matters to you Product Features: Material: Carbon Steel carbon. Shank diameter: 10mm. Diamond coating: 1.5mm. Features: This drill bit diamond removes a full circle from glass, tile, marble, granite, ceramic or other materials. Caution: Always use water for cleaning. lubrication, otherwise the diamond drill bit will burn out. Can be used with a standard electric drill. Make a half round mark at a 45 angle and then hold the drill straight. Reduced drill speed, low drill pressure and increased use of water to keep hole saws cool will significantly extend drill bit life.