Used to resharpen knives; carbide to resharpen dull edges and ceramic to polish for a razor-sharp edge.
Use fine on a regular basis to hone the knife and to reshape your blade.
Use the carbide once or (maximum) twice a year for resharpening (Removing steel).
Remember to think about what you are cutting on. e.g. marble and glass are too hard and will damage the cutting edge of any knife. Bamboo is too hard for European knives. If in doubt ask us for more details.