Features The 3-Step Knife Sharpening kits are designed to sharpen any dull or damaged knives and blades. Stage 1: diamond sharpening rod repairs and straightens damaged blades. Stage 2: slot sharpens to restore its V-shape. stage 3 slot fine tunes for a final best polish. How Our Knife Sharpener Works: Stage 1 - Preparation (High grade Diamond rods). This 'roughens' the knife edge to prepare the surface for sharpening. It also smoothes any nicks and imperfections that could cause the blade to 'catch' during the sharpening stage (a common problem with 1 and 2 stage pull through sharpening slots which can cause damage to blades). Stage 2 - Sharpening (Hardened Tungsten Carbide Plates) - Now pull the blade through slot 2's precision angled tungsten carbide plates to create the perfect sharpened 'V' edge on even the bluntest knife. Stage 3 - Hone (Ceramic Stone Rods) - For final edge honing. It removes any burs and gently polishes the blade edges for a super sharp polish.