Palm 02 Oxygen Analyzer FeaturesSimple to use . . . accurate reliable resultsOne touch calibration . . . 100% O2 or airLong battery life . . . 13,000 hrs of useAdvanced sensor technologyCertified ISO 9001:2008 QA SystemThis palm size oxygen analyzer features an advanced galvanic oxygen sensor that measures from 0.05% to 100% oxygen over a 32 month operating life with no maintenance required. 13,000 hours of battery use and wide variety of optional accessories make it an ideal cost effective choice for checking O2 levels of compressed air scuba tanks and Nitrox mixes. Portable accurate and affordable Durable sealed impact resistant housing One button calibration in either Air or 100% Oxygen User-replaceable Oxygen sensor maintains accuracy Typical sensor life of 36 months