→ 5mm (1/4inch Thick) CLOSED CELL POLYETHYLENE FOAM: enclosed between two layers of radiant reflective 100% aluminum. Strong lightweight, yet durable material that is easy to cut and install and can be stapled or nailed into any surface without compromising the insulation barrier → EFFECTIVE THERMAL RADIANT BARRIER: Reflects 98% of radiant energy (heat) with a thermal resistance. Prevents heat from escaping during colder seasons and does not allow heat to enter during the summer months. → WATER RESISTANT: while being an effective humidity and moisture barrier as well. Can be used in outdoor and indoor applications. → SOUND REDUCTION: Effectively reduces sound travel creating a soundproof environment