These fine ceramic honing rods are what we recommend for daily edge maintenance on carbon steel and hard stainless steel knives. They have a rubber core for durability and a rubber tip for stability. Honing rods do not sharpen your knife, rather they clean up and straighten your edge. A straight cutting edge will give you a much better performance from your knife.
The black rod is hardness 8 MOHS and is in the 6000-8000 grit range.