Packaged 1/4 x 3/8 inch Round End Cylinder Silicon Carbide Grinding Stone, 1/8 inch shank. Compare to Dremel 83142. Silicon Carbide Stones are used for non ferrous metals, like aluminum and brass, as well as very hard metals like carbide. Can also be used on glass, porcelain, ceramic, stones and gemstones. For use with Dremel Rotary Tools.