These are double-sided bench stones with a solid diamond surface on the "fine" side -1000 grit (15 micron) and 300 grit (50 micron) on the "coarse" side. The 8" stone has a unique clearance channel on the "coarse" side- to product faster, cleaner cuts. Both include a pouch, cleaning block and non-slip mat. Use no pressure when sharpening with these stones but please use a lapping fluid to prevent clogging and rusting. Use the "fine" side for achieving a razor edge on planer blades and chisels while using the "coarse" side to repair damaged edges to these tools. Precision flatness gives the ability to also sharpen spindle knives in house. Grit sizes are clearly marked on surface. Guaranteed for five years. Imported.