Genuine OEM Toyota Water Supply Hose via Throttle No.4, part number 16281F2180. This hose is responsible for supplying coolant to the throttle body, aiding in its temperature regulation. It ensures proper engine operation by preventing issues related to throttle body icing or overheating. Constructed from durable, heat-resistant materials designed for the specific routing and conditions within the engine bay. Genuine OEM parts are critical for maintaining the precise coolant flow and temperature control necessary for optimal engine performance and emissions.