Protect your entire fuel system from the harmful effects of ethanol blended fuel as well as clean varnish and carbon deposits from the fuel tank to the tailpipe. For use with cleaning and carbon/water removal and as preventive maintenance with infrequently run engines, such as power equipment and recreational vehicles. Acts as a fuel preservative by adding antioxidants into the fuel because ethanol blended fuel (E-10) is rich in oxygen. It also acts as a fuel catalysis by keeping the hydrocarbon chains short, preventing the fuel from decomposing prematurely. Ethanol Shield is registered with the EPA as is recommended by B3C Fuel Solutions for use with nonroad gasoline engines. 4 oz. bottle.