These instruments are normally equipped with a cable, in some cases with a (special) connector. These transmitters, being continously submersed, have to be perfectly tight during their complete lifetime.
To avoid corrosion, the fluid has to be compatible to the transmitter-housing material. The cable material and the cable seal has to be choosen following their medium compatibility.
The temperature range is limited to max. temperatures of 50°C: higher temperatures will change the cable seal, causing the failure of the instrument. For higher temperatures, we need special solutions.