Bulk Packaged 1/2 x 1 1/2 inch Silicon Carbide Coated Grinding Wheel. Use with 3/16 inch buffing wheel mandrel, not included. Face of buffing wheel is coated with silicon carbide. These are ideal for knife sharpening. Silicon Carbide is for use on stone, glass, ceramics, porcelain and non-ferrous metals. For use with Dremel Rotary Tools.