I use the 1/2 " thick plastic mats (since my carpet is soft underneath) with the red on one side & blue on the other. I ordered mine from a company - BUT they sell them right now at Walmart & Target for the back to school season. They are even cheaper there. They only sell them this time of year, so if you need some - I'd get them now before there gone. I think they are about $7 per mat.
