The Bosch Mass Air Flow Sensor (RS4) - 028021807H is a high-quality sensor designed to accurately measure the amount of air entering the engine. It is specifically designed for use in the RS4 model and is manufactured by Bosch, a trusted brand in the automotive industry. This sensor plays a crucial role in the engine's performance by providing the necessary data for the engine control unit to adjust the air/fuel mixture for optimal combustion. It is made with durable materials and advanced technology to ensure reliable and precise readings. This product is essential for maintaining the performance and efficiency of the RS4 engine.