Oxygen Gas Meter, Digital Portable Automotive O2 Gas Tester, Digital LCD Display Alarm O2 Concentration Measurement Tester Device for Car, Climbing, Tunnel, Laboratory and Industry

Works as good as much higher sensors.User Interface is a little hard to use.

Picture taken around 300' above sea level where O2 content is 20.9%. Shame the accuracy is so poor. It's UI, utility and function are otherwise good.

It cannot read more than 35% O2 purity; so it is limited on what it can read or where it can be used.

After a short while 3rd or 4th use. Got descalibrated. Evenfollowing manual procedures to try calibrate again, it won't. Alarms keep beeping. A waste of time and money.

I tested it by exhaling on it and the reading went down immediately. I blew oxygen on the sensor using a bottle of Boost Oxygen and it shot right up to 25%.The only thing I wish for is if it can read upwards of 50%. The limit at 25% is too low if you are to use this to test oxygen concentrators.

Item arrived. Appeared to work ok. Didn't get to really use it for 1 full year and when I did the only thing that worked was the LED Light. Contacted their support who had me try a couple of things which I did and they didn't work so I restated my original problem that missed the first time. They never responded back. It appeared the unit had an electronic problem at the LED screen would light but that's all it would do... not boot up or screen information. I also learned that most unit sensor under $100 only last about a year.If you only need a unit for less that a year... then this might work... but don't count on any support, Don't waist you money if you need it for more than a few months. I wound up paying $275 for one that will last at least 3 years... and comes with real support.