Norton Premium Bear-Tex Brand
Coarse is Brown, Medium is Burgundy, and Very Fine is Blue.
These belts are commonly used in the metal working for deburring, removing rust and polishing. In the knife business we use them for all that but mostly for putting fine scratch pattern down on the blade. Generally, there are 3 "grits", coarse, medium and fine. There is a difference in the pattern they leave and if you prefer a satin finish blade, these are handy.
These belts wear like iron and will last you for years.
All things considered, get the medium and see how you like them. If you like them, come back for both the coarse and the fine.