US Energy Products XTemp Brand Two layers of polyethylene industrialized air bubbles bonded between two layers of highly reflective metalized aluminum polyester film. (white side/foil side) Industrialized strength, lightweight yet durable insulation designed to hold staples without tearing. Does not compress, collapse or disintegrate. Reflects 97% of radiant heat, emits less than 3% of heat, Class 1 / Class A fire rated radiant barrier that has passed the ASTM E84 test & ASTM E2599. Non-toxic, non-carcinogenic, fiber-free, safe to handle and does not require protective clothing or respirators to install. Easy to install and maintenance free, cuts easily with utility knife or scissors and installs easier than fiberglass. Simply staple, nail or glue into place! No mess, and no itchy fibers! Not affected by moisture or Saves energy by reducing the stress on heating and cooling systems, keeping your home warmer in the winter, and cooler in the summer. It can reduce utility bills substantially all year round. 40 square foot roll (48 Inches wide, 10 feet long )