This design provides a level indication off (colorless) liquids and gases. In a transparent level gauge, a sight glass is mounted on either side of the medium. This way you can see through the media. Due to difference in transparency of the liquid, gas or vapor, the level can be read. At higher temperatures or heavy glass corrosion attach of the medium, mica is fitted. This reduces the visibility slightly, in order to improve the visibility on the rear side there may be a special lamp mounted in order to better read the level. Due to the special lighting, the light refraction/reflection in the liquid, gas or vapor separation surface is better utilized.
The cured transparent borosilicate glass (to DIN 7081) is mounted in a robust stainless steel or mild steel column with flanges.