This is wool prefelt in a natural brown color, made by Felted Sky from small farm US wool. Please note that it does have a lot of vegetable matter in it. Prefelt stands for preliminary felt, meaning it hasn't been all the way felted yet (unlike traditional craft felt). That means you can attach wool fibers to it it very easily.
This is an excellent backing for flat needle felted artwork and is available in two thicknesses and two sizes. The thick version is made from twice as much wool as the thin version. While the thin works for most applications, there are some projects where the thick is better suited. Cut it to the size you need and use it for making your own wool paintings or signs.