24" x 125' Between Joist Insulation w/ Staple Tabs Foil/Double Bubble/Foil (250 sq. ft.)EcoFoil Floor Joist Insulation is engineered to reduce radiant heat transfer and help prevent condensation in floor and wall cavities. Built with two layers of polyethylene bubbles bonded to reflective metalized surfaces, this 1 4"5 16" thick insulation delivers 96% reflectivity and just 4% emissivitymeaning only a small fraction of radiant heat passes through. Instead of slowing heat movement like traditional insulation, it reflects heat away from