Honestly. Go to a hospital and have your heartbeat and spo2 taken.
I did it yesterday at the hospital and considering the price; it wasnt even close to what the hospital reading. Sometimes suggesting my bpm was 10/20 bpm more than it was actually... which makes me suggest that the whole thing is a very sketchy rough estimate pretty much pointless to go off in any sort of professional level(if thats what youre after) but if you just want want random numbers and graphs to go off in relation to your "exercise" then this is definitely the thing to buy 🤣🤣🤣.
Semi good for a gps, stopwatch, or a conventional watch..... But i wouldnt listen to any of the statistics it gives after like; calorie count/bpm/sleep monitor/ecg/stress level etc etc etc etc(pretty much every feature on the whole device). And the contactless payment only links to santander, the least used bank in the whole of the UK...
Still wear it regularly but honestly id give it a 2 out of 5. I just use it as a stopwatch/watch now though. Its atleast 10%/20% incorrect
