Bulk Packaged 25/32 inch Grey Wheel Silicon Carbide Grinding Stone, 1/8 inch shank. Compare to Dremel 85422. 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.