Useful, easy to handle and accurate enough

The unit displays the SpO2 value is within the specification (mean error = 2%) closely. You have to remember that this error indication means that 68% of all measurements within the range X-2 and X% + 2% lie. With 95% probability, the individual values ​​fall therefore in the range of -4% to + 4% around the mean. This accuracy is too low for the medical needs, but in the price sector perfectly normal and okay.

I was with my wife and me find smaller deviations (about half), if one pays attention, which finger you used and how much you put into it. We both delicate fingers and the thumb trotzden seems to be opaque. We use the index or middle finger. Even this we must not put in as much as possible, but must still be forward 3-5 mm air.

If I can count on a reliable value, I agree to the pulse curve. If this andis rhythmically uniform and clean and clear displays "triangles", I get an accurate measurement.

The pulse rate is consistent with the chest strap from our ergometer exact match (max. 1% deviation).

As a physicist and medical scientist, I am very demanding with regard to the accuracy of measurements. But I am also aware of the difficulties in the preparation of corresponding devices. For this price and all accessories I get more than I could hope for.