AFFF stands for Aqueous Film Forming Foam. It is designed to create a film covering all the components in a car that prevents ignition of fuels and oils. AFFF is a water based suppression systems with a concentration of AFFF and an anti-freeze component. AFFF is commonly used to extinguish fuel and oil based fires. AFFF based systems are cheaper than Novec systems due to the cost of the extiniguishent but they are heavier than Novec since you need more AFFF than Novec to achieve the same fire suppression capabilities.