The OxyGuard Mini Probe has a membrane covered galvanic cell that generates an electrical signal proportional to the oxygen pressure it senses, whether it is placed in water, air, oil, wine etc.

Just 15mm in diameter and 101 mm in length it can, for example, be lowered into a wine bottle. The probe acts as a battery with output voltage that is proportional to the oxygen concentration. it does not need an applied voltage or microprocessor controlled electronics in order to function.

The Mini probe has a true zero and a low output impedance, and can be connected to most types of transmitter or metering equipment with input impedance 1 megohm or greater and galvanic isolation if the equipment is connected to other equipment.  Calibration is carried out by placing the probe in air and adjusting the transmitter or metering equipment connected to it.