This example of a vintage combination Coticule / Belgian Blue Whetstone for your consideration measures 178mm x 38mm (7" x 1.5") and is a hard stone with very fine grain and interesting figuring. Although it is very fine it also has good moderate speed cutting ability. This stone has been lapped flat and the edges chamfered on the coticule side and is ready to use. The Belgian Blue back has an unlapped surface and one corner of the coticule side has been chamfered to remove a chip. I have tested it multiple times and it silky smooth and nice fine finisher.
The vintage Belgian Razor Hone box is in good shape aside from some ordinary wear and dirt.
All photos are of the stone dry.