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.