This design provides an excellent level indication off (colorless) liquids and gases. The prism of the reflex level gauge glass light reflects and the level can be properly read. At the interface of the liquid being measured, the light is almost absorbed, causing the liquid coloring dark and the gas part coloring in color. In a reflex level gauge there is only at one side of the medium a sightglass mounted. The thermally toughened reflex borosilicate glass (according to DIN 7081) is mounted in a robust stainless steel or mild steel column. This construction creates a modern level gauge, which can be mounted close to the tank wall.