The idea of a "smart pot", or cloth pot, is to allow root zone to breathe. Insulation does not allow air penetration to root zone to breathe, and therefore, I would have to wonder if that is a good design.
Anyway. The item I posted works great, and is the least expensive for those on a budget.
Nyt order arrived today and the fabric is heavy duty. I am glad to use these at only a cost of approx. 2,25 ea.