I know what ultrafoam is. It is made by Dow and is the same as blue fan fold foam except that it has a white core with a plastic outer layer and does not have the pin holes and waves as the standard fan fold foam has. If you stress it, you will have wrinkles on your nice smooth paint job. It is somewhat tougher than Depron but is somewhat heavier. Take your pick.
Thank you for your offer but I have all the ultrafoam samples I would ever need. BTW, are you sure you're not Kris^?