QuickSilver Ethanol Alcohol Content Test Tube 879172T28 Used to test the percentage of alcohol in fuel for your boat. Ethanol content in fuel can be harmful to engines and components. Easy to Use to check your fuel supply and avoid the use of fuel with ethanol content. Produced by Mercury marine to our stringent original equipment Manufacturer specifications to maximize the performance of your Mercury and Mariner outboard or mercruiser stern drive