The PRIMA OXYGEN METER Model OM-A is an INTRINSICALLY SAFE instrument which measures % Oxygen in workplace atmosphere. The instrument display is driven by the electrochemical sensor output, which is of the order of 1.5 milliamps in Air with voltage of 0.8 volts in open circuit.
These weak output values make the sensor intrinsically safe per IEC. There is no battery power required to drive the galvanometer and therefore no spark can be generated whatsoever. It has an analog display.