Liquid level gauge glass provides direct observation of liquid level in a tank/vessel rising and falling level of the liquid inside the tank/vessel can be observed through the glass assembled in the gauge. Reflex level gauge glass use the R-form sight glasses. One side surface of reflex glass to use flat glass has several grooves for reflecting prism. The principle of the reflex glass is based on the difference in the refractive indices of liquid and gas or in particular of water and steam. Liquid level shows conspicuously dark hard color for liquid space and light white color for empty space.