This reversible fan helps prevent overheating in stop-and-go traffic, designed to fit the most popular cars and trucks, increases gas mileage, improves engine performance, frees the water pump pulley for more RPM, installs in minutes with simple hand tools, and are reversible (mounts in front or back of radiator). Ultra thin design to fit cramped locations. Reinforced glass filled polypropylene blade and plastic housing for minimized weight. Nylon tie mounting kit included. Nominal fan size is based upon approximate overall assembly diameter.