As America's #1 Ethanol Treatment, you can trust STA-BIL 360 Marine to keep your gasoline-powered engine running at peak performance, and is safe for use in all gasoline engines, including 2-cycle and 4-cycle. By preventing the buildup of unwanted gum and varnish, this product is recommended for use in your boat, jet ski, and other nautical gasoline-powered equipment. STA-BIL 360 Marine Ethanol Treatment & Fuel Stabilizer prevents corrosion caused by ethanol blended fuel. Effective in all gasoline blends, including ethanol and non-ethanol, this product helps increase engine power and fuel efficiency. STA-BIL 360 Marine is engineered to combat the negative effects of ethanol-blended fuels. This industry-leading formula prevents corrosion, cleans the fuel system, and prevents the buildup of unwanted gum and varnish ensuring your equipment will be ready to go whenever you need it. 1oz treats 5 gallons of gas. If using with small engine equipment pour directly into your gas can. If adding directly to your boat it is best practice to add STA-BIL 360° Marine before adding fresh fuel at the pump. This product is designed to be added to the fuel as soon as you get it that way you know the fuel is fresh. This formula will also keep gas fresh for up to a year. Use throughout the season to ensure smooth sailing year-round!.