The very coarse 240 grit stone cuts with amazing speed, but as is the nature of these stones, wears somewhat quicker than an oilstone. However, it can easily be re-trued, so this massive 205 x 75 x 50mm lump is going to last a long time. Use for badly nicked edges. Slightly smoother is the 400 grit stone (205 x 75 x 50mm), excellent for reforming the bevels on worn plane irons and chisels. Finally in this category is the 800 grit stone, a top quality Ice Bear brand stone and a real must in the waterstone armoury; this stone is used to flatten the backs of blades and form the edge. It leaves the metal dull but smooth. The 800 grit also measures 200mm x 63mm x 30mm.