48" x 10', square edge roll double bubble foil both sides reflective insulation, 5/16" thick with two layers of aluminum foil, each foil layer is bonded to a touch layer of polyethylene for strength, reflects up to 97% of radiant heat with an r-value up to 14.3 depending on application, can be used for radiant floor applications, crawl spaces, duct insulation, metal buildings, basement walls & attic's, product has been evaluated by icbo, boca, ccmc, sbcci & dade county, easy to install with tape & staples.