I use anything that will hold the batting in. Several of my Spicy Spirals have a thin light blue - probably a poly/cotton blend that I purchased at WalMart for $.99 a yard. Not for that use, but I had it, so I used it. The one I put together today will have any light colored plain fabric 40x60 that I can find around here. $12 a yard on the front and $.99 on the back is fine with me.