3 1/2" diameter leather wheel. Fits into any standard power drill. Simply apply the included buffing compound to the flat leather wheel and let the drill do the work of bringing your edge up to a polished surface. Removes the wire edge burr from stone sharpening - resulting in a keen razor-sharp edge like you've never had before! Rated for 600-800 RPM. Use for the inside radius of gouges, plane blades, wood chisels, draw knives and other tools.