Two grinding wheels (fine and coarse) plus one stropping wheel provide maximum sharpness and polish. Grinds at 18° to 22° angles—the optimum angles recommended by knife manufacturers for best performance. Stropping wheel operates in reverse direction for more efficient blade polishing and removal of burrs. Magnetized drawer under grinding wheel captures metal shavings and makes cleanup easier. Compact footprint makes it easy to use on countertops or store away in cabinets or on shelves. Save on knife-sharpening service charges.