A Top Mounted Magnetic Level Indicator (TMLI) is a type of liquid level gauge that is mounted on the top of a storage tank or vessel to provide a visual indication of the liquid level inside. It consists of a float inside the tank that moves up and down with the level of the liquid, and a magnetic board outside the tank which shows the position of the float. The board is typically equipped with markings to indicate the liquid level at various points. The TMLI is commonly used in various industries, including chemical, petroleum, and water treatment, to monitor the liquid levels in storage tanks and vessels. It is a cost-effective, simple, and reliable solution for measuring liquid levels, and does not require any electrical power to operate.