Ayvaz reflex glass level gauges use the different optical behaviour of liquid and vapour. Liquid appears dark as light is absorbed; vapour appears bright as light is reflected. This design does not show the interface between two different liquids.

Flanged connections. Maximum pressure: 16 bar. Maximum operating temperature: 250 °C. Applications include steam boilers, filling and discharge vessels, fuel tanks, chemical plants, petroleum tanks and open or closed vessels.