Transparent Liquid Level Gauge consists of a metal body, machined to have an internal chamber and one or more front windows (on each side of the gauge).
On each window a special high resistance plate transparent glass is applied with sealing joint and metal cover plate hold by bolts and nuts.

The chamber is connected to vessel with cross fittings and flanged, threaded or welded ends. Usually, between the instrument and its connecting ends, valves are fitted to consent shut-off piping and to disassemble the level gauge without  emptying the vessel. Drain valves can also be fitted to cross fittings device.
To avoid leakage in case of glass breakage, safety ball-check device can be provided in cross-fittings or shut-off valves.

To protect glass surfaces from corrosive action of the process fluid, Transparent Level Gauges can be fitted with CAF, Mica shields or PTFE shields.
This kind of indicator is suitable for liquids colorless and very fluid.