24" x 50', Square Edge Roll Double Bubble Foil Both Sides, Reflective Foil Insulation, 5/16" Thick With Two Outer Layers Of Aluminum Foil, Each Foil Layer Is Bonded To A Touch Layer Of Polyethylene For Strenth, Reflects Up To 97% Of The Radiant Heat With An R-Value Of Up To 14.3 Depending On Application, Excellent Vapor Barrier For Below Grade Installation, Class A/Class 1 Fire Rating, Approved By BOCA, ICBO, SBCCI, CCMC, FTC-Compliant, Is Non-Toxic, Non-Carcinogenic, Lightweight & Can Be Installed With Scissors, Staples & Tape, Hundreds Of Applications: Wall, Roof & Basement, Garage Door, Camper, Metal Or Pole Barn, Window Coverings, Stables, Hatcheries, Etc, Sell By Linear Foot Or Roll.