Presto electric 3-stage knife sharpener provides professional results at home. Stage 1 - coarse grinding begins the process by creating the proper sharpening angle. Stage 2 - medium grinding continues the sharpening by giving the blade a precision edge. Stage 3- extra fine grit ceramic wheel polishes the blade to a razor sharp edge. Blade thickness selector adjust guides to optimum sharpening angle. Select thick for hunting knives， medium for chef's knives and standard kitchen knives， and thin for light blades like fillet and paring knives. Suction cup feet provide added stability. 13.75 In. L. x 4.5 In. H.