(Synonymous with proximity photoelectric sensor) A proximity photo sensor is capable of detecting the presence of an object by using light and emitter-detector pairs to measure changes in light. Since it does not rely on contact, less damage is made to the sensor, increasing its lifetime when used in high-cycle applications, such as beverage plant bottle counting or semiconductor wafer handling. Knobs for sensitivity adjustment also enable users to set the volume accurately according to the size of the target and level of ambient light.