I just picked up some new Nike cycling shoes with carbon fiber soles, and in the box there are two "gasket" type things which I assume go between the shoe and the cleat, but I don't see what the purpose of it is. One side is smooth and the other side has a rough surface almost like sandpaper. I am relatively new when it comes to shoes since this is only the second pair I have had, and the first pair I had didn't have this "gasket". Can someone tell me what these are for and if I even need to use them? Thanks alot.