Depending on what type of head you' re using makes all the difference in selecting the right sharpener. For two blades (and even many three-blades), I' ve found nothing that works quicker and more efficiently than the redi-edge; a carbide sharpener that makes sharpening a no-brainer. If you have replacable blades, you can remove the blades and use a diamond hone. I do this all the time. But you' ve got to be pretty slick at sharpening to get most of them back to a sharpness approaching the factory grind.