OK. So it is a bit more than just polyurethane foam. The website I pulled up on the product you mentioned was all in French, so I couldn't tell the specifics. There are a lot of products on www.foamtapes.net . Wow, 25% the cost of the windows is pretty significant. Let me know what you think of the products at foamtapes.net, their prices are really reasonable, if you can find something comparable.