this fuel check valve will keep the fuel from siphoning back toward the tank when the engine shuts off. This product aims to improve starts, providing peace of mind for automotive enthusiasts and professionals.The Russell Barbed Check Valve is engineered for easy integration into fuel lines, ensuring one-way flow to prevent backflow and maintain system integrity. The barbed fittings are designed for a secure connection, allowing the valve to be easily installed without requiring specialized tools. Available in 5/16” and 3/8” sizes, the valve is compatible with a wide range of rubber and synthetic hoses, making it suitable for numerous automotive applications.Manufactured from high-quality 6061 aluminum, the Russell Barbed Fuel Check Valve is built to withstand the harsh conditions commonly found in automotive environments but is incompatible with E85 or methanol-based fuels. Its corrosion-resistant construction ensures long-lasting performance, while the compact design makes it easy to install even in tight spaces. They will work on fuel systems with a minimum of 3 psi and a maximum of 10 psi of fuel pressure. Russell Barbed Fuel Check Valves come in a black anodized finish to complement the looks of hose installation and Russell Hose Ends.