short description is not available Material: the frosted sponge is made of high-quality brown corundum, using high-density sponge as the basic material. Different specifications: (coarse, medium, fine and ultra-fine-4 different grades), coarse (grade 60-80), medium (grade 100-180), fine (grade 240-320) and ultra-fine (grade 400-600) are less, the coarser the particle size is, the higher the efficiency of polishing effect is, but the coarser the grinding effect is, the reverse is the case; it is recommended to use according to the characteristics of the goods and polishing requirements Both dry and wet: the sandpaper block can be cleaned and reused, and can be used for both dry and wet. Block is easy to handle, durable and not easy to tear Widely used: can be used for wood, glass, paint, metal, plastic, porcelain The size of each grinding block is 3.9 * 2.7 * 1inch / 10 * 7 * 2.5cm