Here in this case this indicator is used as a direct local level indicator mounted on the top of the vessel or RCC tank. The float is made out of SS304/ SS316/ PP/ PVDF/ PTFE/ PVC etc. As the level inside the tank rises the float, which buoys up, moves the connecting pipe to the region of visibility on top.
For Transmitter Type
The magnet holder attached on top of the connecting stem of the float buoys up along with the level rise and it cuts in or out a series of resistors kept sealed outside the level