Chef's Choice Pronto Manual Diamond Hone Sharpener 464 is the fastest manual sharpener on the market. The 464 includes two stages, one for sharpening and a second for honing/polishing for a razor-sharp, arch- shaped edge that is strong and durable. 100% diamond abrasives are used in Stages 1 and 2, and the diamond abrasive wheel will hold shape indefinitely, and sharpen any alloy knife. Micron size diamond abrasives in stage 2 leave your knife with a super sharp polished edge. The precise bevel angle control sharpens to a 20 degree edge. The Pronto is safe to use on straight edge and serrated knives; kitchen and household knives, pocket knives and fish filet knives.