I’ve got one which looks like this and I bought from eBay/China:
It practically shows me that I am in a coma when I am on the ground (a reading of 83%) and if my finger gets a bit wet (sweaty) or vibrates (in the air) it shows no sign of me existing at all (no reading). I tested it on several other people with similar results, so this is definitely not a good one.
I’ve seen Peter’s thread and the link to healthcare4all but there are many of those at different prices. Can anyone recommend any good one? Is anything from eBay worth looking at? What about the one from Aerox for 99 EUR or are there the same/better ones for less money?
I have this one
https://www.pulox.de/po-100-v?gclid=CJ6zoaz5tswCFQccGwodgdoMXw
and satisfied since two years, although it is not so good readable in very bright sunlight. The values shown are plausible at least.
I would go for a good name e.g. Nonin. I paid about £300 for my first one, 13 years ago:
It still works although I had to bodge a microswitch on the outside of it for the auto turn-on 
They do much cheaper ones now and they are just as accurate.
The market is flooded with chinese crap…
There are also modern smartphones which can do this… well, sort of I now have the S7 but won’t even bother to activate the Samsung Health stuff on it.
I have one that’s not too dissimilar to Vladimir’s. A bit different, but not too much. It too was a Chinese one from eBay.
It works well, and gives similar readings to Peter’s.
I’d suggest that you complain to the vendor, and they will most likely send you a new one free of charge. Hopefully yours was just a broken one. That’s how they seem to work. Low quality controls, so most are good, but a higher percentage than might be expected are faulty. Then they replace those when the customer complains.
Well, this looks identical to the one that I go. Maybe I was just lucky.
I have the Pulox and it works very well under all circumstances as far as I can tell.
