I had some Block-IR from CAP and I also stopped by Lowe's for Reflectix. They are almost the same product. Imagine thin layers of bubble wrap with foil on each side; that's what these products are. I believe the Reflectix brand may be superior because I saw a double-layer of bubble insulation versus a single layer of bubble insulation in the Block-IR. Lastly, Reflectix is a bit cheaper than Block-IR. 4'x25' roll costed me $44ish + tax. Horticulture.source.com has the Block-IR 4'x100' for $200 + shipping.