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 AND MOLD 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 At USEP we are committed to designing quality products that we know you will love. If for any reason you are not completely satisfied, contact us so that we can be of assistance.Roll Size: 48inches Wide x 100INCHES Long