10-35 Db noise reduction. 1" thick barrier consists of two layers of fire retardant foam sandwiching a layer of 1 lb./sq.ft. mass loaded vinyl. Finish is a 1 mil reflective, aluminized, ripstop reinforced mylar facing. Use for larger gasoline and all diesel engines for maximum quieting. Use a double layer for severe applications (up to 50 Db noise reduction). Do not use in areas where temperature exceeds 250°F.