Bora 501098 Fine/Coarse Combination Sharpening Stone, Green Silicon The coarse 240 grit lighter side is for final honing or touchups and the fine 320 grit dark side is for basic sharpening, removing nicks etc. Ideal size for bench work Measures 6" x 2" x 1" Intended for sharpening all types of tools and knives 1 year warranty