This file set has two grit sizes: coarse and fine. The coarse grit is 50Grit, which has a rougher than the fine grit and is faster for polishing and engraving. The fine grit is 116Grit, which has a smaller grit and a finer grinding. This set includes different sizes of grinding head diameters, which is very suitable for crafts from rough processing to fine processing. This stone carving tools is equipped with a universal handle of 1.7 inches (45 mm) in length and 1/8 inches (3 mm) in diameter, which is suitable for most rotary tools. Tools such as electric hand drills, electric grinders, small machines, etc. can all be used with grinding bits. grinding bits are suitable for grinding and carving hard materials such as jade. Water cooling is required during use, and relevant should be worn. Our nail drill bits are made of electroplating technology and good-quality particles, which are not easy to fall off and can a longer use time. The grinding bit has uniform particles and sand. It can grind quickly when engraving hard materials such as glass, improving the efficiency of engraving. Its performance is stable and has a certain impact force, which can reduce the number of times the grinding head needs to be replaced. This glass drill bit has a wide range of applications. It is not only suitable for stone carving, but also for grinding and carving hard materials such as jade, glass, ceramics, carbide, crystal, metal, etc. This grinding bit set is very suitable for home decoration and handicraft DIY. It is a good helper for engravers for polishing, grinding, drilling, cutting, engraving, etc., Weight: 0.51698400439 Pounds, Manufacturer: Kueohse