I think it is coir mat too. I've seen it somewhere in the plant shops and also have been thinking to convert them into some kind of hiding place. Bad thing it is not usable outdoor, I think rain will go through it easily...
It is a coir mat. I was walking around lowes and I was like oh I could turn that upside down and cut a hole in it! So far works great but then again I'm sure if you put it outside the rain would probably mess it up. So I decided to keep it in the indoor pen. Just was super excited and thought I would share