Super Shield Reflective Insulation is a 5-layer, non perforated, reflective energy-shield. It?s two outer layers of 99% aluminum foil reflect 97% of radiant heat. Each layer of foil is bonded to a tough layer of Mylar and has an interwoven nylon scrim for extra added strength. It's so strong it's virtually impossible to tear! It also has a Class 1, Class A fire rating! You?ll find that hot and cold spots in your home are eliminated summer and winter. You?ll find yourself enjoying greater comfort in your home. And, since it doesn?t use energy to increase your level of comfort, you?ll have lower utility bills.