Nidec Copal Electronics' WL10 series liquid leak sensors use optical technology to detect leaks. Light from an LED is reflected off of a prism into a detector. When liquid reaches the prism the light from the LED is reduced, the detector senses this reduction of light. The detector then sends a signal changing the status LED from green to red.

These are available in two different housing material options. The customer can select the PP or PFA housings, dependent upon the chemicals that the detectors will be exposed to. Potential applications are manufacturing equipment for semiconductors, liquid crystals, coating machines, gas scrubbers, and etching and lithography machinery.