IMPORTANT: Please remove your sharpening wheel and clearly measure the diameter of the screw interface before purchasing. Avoid situations that lead to adjustment errors. This replacement sharpening disc set is only an accessory for the roller knife sharpener and cannot be used alone. The package does not include the roller handle and magnetic base, only two replacement sharpening discs. 400# Diamond Grinding WheelThe diamond material is hard and suitable for sharpening, repairing, and straightening old or dull knives and damaged blades. It is not recommended to use it too frequently or too hard at the same time, otherwise it will scratch the surface of the knife. 1000# Ordinary Grinding Wheel - Fine Grinding: Used for fine grinding, polishing, deburring, and improving the sharpness of blades. Suitable for daily knife sharpening. Professional Knife Sharpener: This is a newly upgraded knife sharpener. Using the roller sharpener can keep your knife blade in new condition for longer. With just a light press on the roller, anyone can sharpen their knives as quickly as a pro. No electricity/water required, just a clear view.