In our long experience, they are proven very reliable. ​We see approximately a 0.1% failure rate of successfully installed sensors (i.e. not counting those that were DOA due to g-force impact during shipping) or about 1 sensor per 1,000. The PSR series oxygen sensors are manufactured by Analytical Industries, a major supplier of galvanic oxygen sensors for the rebreather market, who has been making our Dive Gear Express replacement sensors for the last 15 years.

We make an effort to retrieve failing sensors less than 12 months old for testing and microscopic examination by the factory. By far the largest cause for reports of suspect sensors that otherwise turn out to be functioning normally is corrosion & contamination in the rebreather wiring and connector. Some of the other failures appear to be the result of exposure to excessive heat or salt water, or mishandling such as impact in the rebreather itself. The most common cause of sensors becoming current limited early is the sensor was exposed to elevated oxygen levels for an extended period -- that typically happens when the breathing loop was not flushed completely with diluent following calibration (or was not aired out following diving) and then the rebreather sits unused.