Reflectix® BP24010 Double Reflective Insulation, 24" x 10'5 16" thick with two outer layers of aluminum foil. Each foil layer is bonded to a tough layer of polyethylene for strength. Reflects up to 97% of radiant heat with an R value up to 14. 3 depending on application. Excellent vapor barrier for below grade. Can be used for radiant floors, crawl spaces, duct insulation, metal buildings, basement walls & attics. Square edge roll double bubble foil both sides 5 16" thick with two outer layers of aluminum