The Pierburg Secondary Air Injection Pump Check Valve - 722560420 is a component designed to regulate the flow of air in a secondary air injection system. This system is responsible for reducing harmful emissions in a vehicle by introducing fresh air into the exhaust stream. The check valve ensures that the air flows in the correct direction, preventing backflow and potential damage to the system. It is a crucial part of the emissions control system and is often found in vehicles with gasoline engines. The Pierburg Secondary Air Injection Pump Check Valve - 722560420 is a high-quality and reliable product that helps to maintain the proper functioning of the secondary air injection system.