2pcs 3/8" Fuel Check Valve One Way Inline Non-Return for Diesel Gasoline 10mm Product Description: High-Quality 3/8" Inline Check Valves for Fuel & Fluid Systems Ensure consistent fuel flow and prevent backflow with these durable aluminum one-way check valves, designed for gasoline, diesel, oil, and water systems. Each valve features a clear flow-direction arrow and is compatible with 10mm (3/8") inner diameter hoses, making it ideal for automotive, marine, RV, and agricultural applications. Key Features: Material: Heavy-duty aluminum construction (longer lifespan than plastic valves). .