It seems to have a metal finish & that is why it can't be used in the microwave.
Yes you are correct. I was thinking of the insulbrite product from the warmcompany.
I've never seen anything like this before. It does sound like an interesting and useful product. I see that they have it at Joann's online. Would be interested in seeing how it works for you.
I will let you know! I hope to use it soon, as soon as I get my backlog handled. Lol!