Design Engineering's Boom Mat premium quality damping material is available in two thicknesses: 2mm and 4mm. The 2mm version is 33 percent thicker than the company's original damping material and provides extreme noise damping. Boom Mat XL is 4mm thick and is 166 percent thicker than standard damping products. Both sizes are constructed using a thick aluminum panel-stiffening skin and an odorless pure butyl noise constraining layer and together these materials trap unwanted noises. Both the 2mm and thicker 4mm Boom Mat XL materials are flexible, easy to trim and can be applied on flat and irregular surfaces.