Cratex #88-2M 1/8" Hole Rubberized Abrasive Wheels 1"x1/4" Medium Grit, Pack of 6 Grit Textures: Each Cratex size and shape is made in four standard grit textures or compositions which differ in accordance with the mesh size of the abrasive grain used. Coarse (Green) Medium (Dark Brown) Fine (Reddish Brown) and Extra Fine (Grey Green). Available in diameters from 5/8" to 1". Supplied with 1/16" center hole and can be used with mandrels with 3/32" or 1/8" shanks in power tools with safe maximum operating speed of 25,000 RPM. They can be used on countless operations requiring absolute control of metal removal such as in micro-deburring, relieving stress concentration areas and polishing away fatigue lines, scratches and other surface defects. Ideal for work on dies, instruments, control mechanisms, electronic parts, jewelry, aerospace components, plastic articles, light castings,, models, and super sensitive scientific devices. Used by Professional Jewelers