Dremel 2-Pack 3/16" Grinder 1/8" Shank for sharpening, deburring, and general-purpose grinding on harder materials. With a 1/8" shank and a 3/16" diameter, this grinding stone is made of durable silicone carbide and has a speed rating of 35,000 rpm. It is green in color and includes (2) bits. Dremel silicon carbide grinding stone is designed to grind and etch stone, glass, ceramics, porcelain, and non-ferrous metals.