Phos-Chek® WD881 Class A foam was introduced over 20 years ago and has been widely used by government agencies around the world who are responsible for municipal, wildland, and industrial fire management. Phos-Chek WD 881 Class A foam concentrates continue to be the product of choice based on unparalleled superior performance. Phos-Chek Class A foam concentrates are specifically formulated to make water more effective. The unique combination of surfactants significantly reduces water's surface tension, creates a superior foam blanket when mixed with air that surrounds fuels with a thick layer of water, creates a barrier between the fuel and the fire, allows fire fighters to see application areas, and knocks down fire faster than water alone. Phos-Chek WD 881 performs exceptionally well in all foam application equipment including Compressed Air Foam (CAFS) systems.