Pride Abrasive 400 Grit Coarse Sharpening Stone, 20cmx7cm surface, 2cm thick.
These are high quality, American-made water stones. They cut very fast and yet are still very long lasting. Highly recommended! This 400-grit is quite coarse and a great place to start with a very dull or damaged knife -- you can make quick progress in cutting a new edge!
These are fine to soak before sharpening, but as always air dry between use, and avoid rapid temperature changes to reduce the risk of damage. Only use water to lubricate and clean, no oil or detergents or anything else.
Note: these do not come with any packaging. They will ship to you well-protected, but they do not include any box or stand or anything else.