The Round and Square covers are interchangeable. I bought OEM's for the Rounds and a Slippery for the Square because I thought they would be different fits. Boy, I was wrong. I could have saved some dollars if I known before. FWI: The Slippery Cover is superior to the OEM Covers. They are heavier denier nylon and they have a zipper in the back so you can access the tray. IMO