The Slide Sharp uses a unique system of injection molded nylon guides to hold the knife edge at the specific angle required for optimum sharpening. A hardwood base holds a porcelain sharpening rod. Simply insert the rod in the base, slide a return spring over it, select the sharpening guide needed for your knife, and slide on the cap. Sharpening action couldn't be easier. Just pull your blade through a sharpening guide slot pressing down lightly. The return spring pops the guide up again for the next stroke. You then repeat the same action as needed in the opposite slot, sharpening both sides of the blade equally, or as needed. Two sharpening guides are included. One is a slight angle for putting an edge on sport, work, tactical and kitchen knives. The second has a steeper angle for heavier tools such as choppers and machetes. The Slide Sharp system comes with two porcelain sharpening rods. You start with the coarser gray rod, and finish the edge with the fine white rod.