This is basically a flexible plastic-like material that forms an attenuating/reflecting sound barrier. The product is made of 25% P.V.C. loaded and spread evenly with Barium mineral powder which takes up the other 75% (by weight) of the product. The Barium mineral is very heavy and makes the vinyl heavy and impenetrable to sound waves. It's sort of like if lead was plastic! It weighs 4kgs per square metre. It is ideal for any surface that needs to be deadened e.g. car door or floor panels. It completely damps (ie prevents) any panel resonating from high power speakers. It is also amazing for attenuating road noise from steel car floors, etc. It can be cut with a hobby knife or good scissors etc. The material is held in place with spray or gel contact cement. One sheet is generally enough for the average car door. This product is superior to the AX-3680 previously sold. Sound transmission class: 26 Humidity: Unaffected Stability: Indefinite Supplied in a polythene bag Petrol/Diesel: Moderate Acetone: Good 10% HCl: Good 10% NaOH: Poor Density: 1.74g/cm3 Tensile: 3000N/50mm Elongation: 0.2% Working Temp: 0C to 95C