TridexC6 3-3% and 3-6% are AR-AFFF concentrates with a special biosynthesized polymer. This polymer is designed to fulfill two functions. The first is to form a protective membrane between the fuel and the foam as it contacts the water-miscible fuel, making extinguishment possible. The second function is to make the foam more stable and heat-resistant, resulting in better burnback resistance and sealability compared to conventional AFFF’s. The concentrate formulation is recognized by United States Patents 4,999,119 and 5,207,932.