The Pierburg Porsche Secondary Air Injection Check Valve - 705817000 is a component designed for use in Porsche vehicles to regulate the flow of secondary air into the engine. This valve helps to reduce emissions and improve engine performance by allowing fresh air to enter the exhaust system. It is made by Pierburg, a reputable manufacturer of automotive parts, and is specifically designed for use in Porsche vehicles. The check valve is an important part of the secondary air injection system and ensures that the air flow is properly controlled. It is a high-quality and reliable product that is essential for the proper functioning of the vehicle's emission control system.