The Vemo Coolant Level Sensor (part number V207200561) is a sensor designed to monitor the level of coolant in a vehicle's cooling system. It is typically installed in the radiator or coolant reservoir and sends a signal to the vehicle's computer when the coolant level drops below a certain threshold. This allows the driver to be alerted to potential leaks or low coolant levels before they cause damage to the engine. The sensor is made by Vemo, a trusted manufacturer of automotive sensors and components.