Tubular type level gauge are widely used for low pressure services upto 7 Kgf/cm2 and maxium temperature of 80℃. Check balls are built in the upper and bottom valves to stop flow instaneousely when the glass is broken. A cylinder like sheet metal protector is available to prevent glas breakage from external sources. For those gauges for their center to center dimensions in excess of 1,800mm, intermediate couplings are used to connect tubular glassed.
Depending on nature of liquids, tubes made of various plastic resin are also available. Tubular glass with a linear red coating on the back is available to make level observation more clear.