Our Deluxe Waterstones are fired from aluminum oxide abrasive carefully screened for consistent size mixed into a clay matrix. Their size is 8-1/8˝ x 2- 5/8˝ x 1- 3/8˝. They are manufactured to create a porous, friable surface. This is important since, as the blade is rubbed on the stone, the particles of abrasive become rounded and dulled. The waterstones'' porous, friable nature keeps fresh, sharp abrasive constantly exposed on the surface, thus accelerating and optimizing the cutting effect. We offer two classes of stone: coarse and finishing. The coarse stones are 250, 800, 1000, and 1200 grit. The 250 and 800 grit are faster cutting and used for repairing nicked edges or reshaping a bevel. The 1000 or 1200 grit stones are used for the first stage of the actual sharpening. Japanese water stones are softer than Western styles causing a fresh, sharp surface to be continually exposed to the tool edge. Full instructions for care and use are included with each stone.