WHY USE FLAT GLASS GAUGES Flat Glass Gauges have been in use for over 100 years. They give you the ability to directly view the process fluid under temperature/pressure conditions that would render most other level technologies useless. Their construction is very robust, and reliable. They define the term “simple to use”. After installation, the only tool you will need is your eyes. Flat Glass Gauges are relatively inexpensive as compared to most other level technologies. Other Features They do not need electrical power to operate. This can be a great advantage in the case of a power outage. Simple to install – no calibration is necessary. Can be used as a reference to check, or calibrate, other level technologies. Pressure rating from vacuum to 4000 psig (275.79 bar). Temperature rating from -150oF (-101.1°C) to 750oF (398.8°C) Stainless Steel / -50oF (-45.5°C) to 750oF (398.8°C) Carbon Steel Not affected by the chemical or electrical properties of the process liquid. Specific gravity, dielectric, conductivity, surface turbulence, vapor, foam, etc. no longer needs to be considered.