Nothing about Gransfors Bruks is inexpensive and that includes the various aftermarket items that you might want to go with your axe. Most of the axe masks that you find are very well crafted and beautiful to look at but very expensive. They are also usually made of leather which certainly works but a hard axe mask/bit cover can be a nice safety item on sharp axe that is carried in a pack. That is why I was so happy to come across Grizzly Outdoors. They offer an axe mask for the Gransfors Bruks Small Forest Axe that is molded from kydex and costs only $15. In that world of Gransfors Bruks, that is a bargain of the highest degree.
Check out Grizzly Outdoors.