STA-BIL fuel stabilizer keeps fuel fresh for quick starts after storage and all year round. Prevents fuel deterioration (fuel begins to break down after 60 days). Prevents the formation of gum and varnish. Corrosion inhibitor prevents rust. Protects the fuel system during storage. Helps keep the carburetor, fuel injectors, and fuel line clean. Eliminates the need to drain fuel. Comes in sizes that fit your specific needs. Twin-neck bottle offers quick, convenient measurement and dispensing for large or small amounts. STA-BIL will stabilize fresh fuel and protect an engine's fuel system up to 15 months when used as directed. For best results, treat fresh fuel promptly when opened, once bottle is opened it has a shelf life of 2 years.