The 4000 Grit Deluxe Finish Stone is fired from 6000 grit abrasive mixed with a clay binder and no plastic binders additives.
It is a water stone and should be kept wet during use and allowed to dry between uses. As you sharpen, a slurry is formed by the mixture of clay, water and steel. This slurry is an integral part of the sharpening process.
Although you can certainly move to a finer grit stone from this one, this 4000 grit stone is excellent for polishing.