Ideal for all quality knives including fine edge and serrated, kitchen and household as well as sports and pocket knives, the M250 creates a triple bevel edge using three successive stages. The first and second stages are electric and use 100% diamond abrasives for shaping and sharpening the first two edge bevels. Stage 3 hones and polishes the third bevel using ultra fine diamonds for a razor sharp, arch-shaped, professional edge that is stronger and more durable than conventional V-shaped or hollow ground edges. Since it is the manual stage, Stage 3 can be used anytime, and anywhere without power! It also sharpens serrated edges. One year limited warranty. Engineered and assembled in the USA.