This product is made of high quality emery, made of the most electroplating technology, with small precision and precision. Especially suitable for polishing very hard materials, suitable for grinding glass , ceramics after drilling, hole burrs and chamfering. Smooth and beautiful grinding head surface, durable thick and even sand coating! Note: it is better to add water for cooling during the grinding process, which will increase the service life. Material: This product is made of high quality emery, made with the technology of most advanced electroplating, and the precision is accurate and the error is small. Application: It is especially suitable for grinding super-hard materials, suitable for grinding, hole countersinking and chamfering after drilling glass and ceramic tiles. Shank diameter: 6 mm Diameter: 20 mm