Magnetic flap level indicators, also called magnetic float level meters, operate on principles of buoyancy and magnetic coupling. As the liquid level in the measured container rises or falls, so does the magnetic float within the main tube of the level meter. The permanent magnet inside the float transfers its position via magnetic coupling to the magnetic flaps indicator, flipping red and white flaps 180°—white turns red as the level rises and red turns white as it drops. The boundary between red and white indicates the actual liquid level inside the container, providing a clear visual indication of the level.