Second Skin Damplifier - 40 Square Feet Bulk Pack MADE IN THE USA - 300% more efficient than tar boards and asphalt mats. The quality of the the butyl rubber and thickness of the foil create the overall effectiveness of any sound deadener. Roofing products are frequently labeled as sound insulation. However they are typically made overseas from inexpensive alternatives to butyl rubber such as asphalt, tar, or bitumen with very thin foil or Mylar. Although less expensive, they are much lower quality, will not perform well, and may out-gas harmful vapors and/or melt and fall off. The true performance of Damplifier comes from details you cannot see, such as the unique chemistry of the high performance US made butyl rubber. Damplifier is made of 1 mm thick elastomeric butyl rubber with a 6.5 mil black annealed foil constraint layer. The thermal range is -75F(-60C) to 450F(232C). and will not melt, out-gas or fall off. Damplifier is ROHS compliant, an EU standard restricting the use of 10 hazardous substances. CHAD UTT, WEST COAST CUSTOMS OPERATIONS MANAGER: We skinned the entire vehicle floor, walls, doors, and roof with Second Skin Damplifier Pro and the Luxury Foam padding. I am blown away by how quiet and dead the sheet metal is. I would have to layer up competitor product three, four, sometimes five layers thick to achieve the same results. Awesome stuff man!!!!! Really, REALLY, happy with the product!!!