I grabbed one of them out of the box yesterday to play with. They are advertised as being made of 600 denier polyester. First thing I tried was some Oracal 651 sign vinyl. Not gonna happen, it just would not stick to the seat. I couldn't even get the release paper to peal off the decal.
Next up, I cut a piece of Eco Film Plus. When I grabbed the roll, I also noticed it had a sticker inside the other end of the tube that says Video Flex Extra but it doesn't have the pink layer like the roll of Video Flex Extra I have??? Anyway, I heat pressed that onto the seat and it looks like it will work. I used some scrap papers left over from transfers to block off around the design and I don't see any evidence of discoloration from the heat press.
I will probably try Easy Weed on the other side just to see what happens.