The QS30H2O product line was developed to detect the presence of water and water-based liquids. The typical application is verifying liquid fill on bottling lines and packaging machines. The sensors can also be used to verify water flow at a nozzle, or detect liquid level in a sight glass The sensor combines very high optical power to penetrate the clear or translucent container, yet remains very sensitive to the presence of water which absorbs the 1450 nm light. In the event that the sensor is burning though both the container and the liquid contents, the system gain should be reduced with apertures, increased separation distance, or mis-alignment of the sensors.