Level meter according to the buoyancy principle and principle of magnetic coupling work. When the measured liquid level container movements, the level gauge led tube also will lift the float, float within the permanent magnet passes through the magnetic coupling to the scene indicator, turning red column driver switch 180 °, when the liquid bits increases, the turn from white to red column, when the liquid level when the column turned from red to white, indicator of the red, white circles located at the medium level for the container and the actual height to achieve the level of instruction .