Genuine OEM Volkswagen Vacuum Check Valve, part number 058905291N. This small, essential component is designed to control the flow of vacuum in one direction, preventing back-pressure and ensuring proper system function. It is typically found within the engine's vacuum lines or emissions system. Made from durable black plastic, it weighs approximately 0.01 kg. Using a genuine OEM check valve guarantees precise opening and closing pressures, critical for maintaining engine performance and emissions compliance.