Grindstone Glass 400 grit Splash & Go from Satake are ceramic stones with a glass bottom that provide stability and durability. The glass base allows the stones to be used down to the last millimeter without cracks and makes both the logo and grit visible. The stones are used with water without pre-soaking. The coarse 400 grit stone is used for rough sharpening and repairing damaged knives. Comes with a whetstone holder and English sharpening instructions with illustrations.