I picked out something that was close to the original density. One block was mint green, the other was an off-white color. They had another block that was a light blue color. It's not real precise. What you don't want to do is to have a block that does not go all the way across the bench seat. Think foam rubber pillow as far as density is conerned. You don't want the really hard black stuff. It'll give you flat spots on your butt and saddle sores. (LOL)