Yupo.

Yupo is a synthetic watercolor paper. In fact, it's not paper. It's 100% polypropylene. I haven't done much watercolor painting ever but when I did do it, the wetting and stretching of the paper seemed a lot of work and even then my paintings bubbled. Yupo did what it promised and it was easy to work with and on. Worth a try if you are into watercolors.