It never ceases to amaze me how our equipment keeps getting smaller, lighter, and less expensive, while at the same time offering more features. While this is most commonly seen in personal computers and cell phones, it happens with dive gear as well. The OxyCheq Expedition Oxygen Analyzer is one example.

While I have not been unhappy with my current analyzers, I am always keeping my eyes open for "new toys." The Expedition Oxygen Analyzer fits into this category, even though it is definitely not a "toy." This compact analyzer is smaller than any I have seen (slightly smaller than the Analox, and significantly smaller than the OMS analyzer), is splash proof, and is extremely reasonably priced.The molded ABS case is sealed to protect the sensor, digital meter, on/off switch, and electronics inside. The sensor is a threaded o-ring seal, the LCD panel and calibration knobs are sealed with gaskets, and the back is 0-ring sealed. Calibration is simple, and so far has remained very stable. In fact, I have not had to recalibrate at all (although, given the fact that I have only been using it for a month or so, I am still waiting to see just how well it does). The analyzer has a removable cap that contains an integrated flow restrictor, so that eliminates one piece when compared to my current system.

Response time on the sensor is been rapid, making gas analysis simple. In fact, my technical diving students unanimously agree that they prefer this analyzer for that single reason to the other two I own. It can be calibrated with either 100% oxygen or air. Resolution is 0.1% at 1 atmosphere, with a measurement range of 0.1 to 100% oxygen.

Sensor life is supposed to be at least three years (in air) and batteries should last about two years, depending on use. The sensor is user replaceable, and is about half the cost of others I have bought. The three AAA-cell batteries are also user replaceable. One nice feature when compared to my Analox is that when you remove the back, nothing is attached to it. This makes replacing both the sensor and batteries much easier.

One feature I especially like is the backlighting, which makes reading the digital display much easier during dusk or night diving operations. The Expedition Oxygen Analyzer comes packaged in a durable plastic box. This case has ample room for spare batteries, sensor, or the optional remote flow restrictor.

The unit comes with a one-year warranty for manufacturing defects, which does not include sensor or battery replacement due to normal usage. The only concern I have is that the company making the unit is quite small, and has a limited product line. However, the owner, Patrick Duffy, has been active in the technical diving arena for many years, and has an