Ethanol Shield is needed to protect your entire fuel system from the harmful effects of ethanol blended fuel. Ethanol Shield envelopes water molecules as they are introduced into the fuel system preventing them from bonding with the Ethanol. By enveloping the water it now pass harmlessly through the fuel system including all filters and screens to be vaporized in the combustion chamber. This process is what puts an end to the majority of problems like phase separation that leads to the corrosive affects we see with ethanol. It also has dual lubricants that condition the rubber and plastic components, they also rejuvenate and protect the rubber gaskets and seals that may have been dried out form ethanol. After the fuel is burned in the combustion chamber a synthetic lubricant is left lubricating the entire upper combustion chamber such as piston rings and valves. Ethanol Shield Creates a better bond between ethanol blended fuel (E-10) and 2 cycle oil. All 2 cycle oils do not bond with ethanol, hence the reasoning most manufactures recommend not to go over 10% ethanol content and to shake your 2 cycle oil gas mixture before running.