I just ‘finally’ received the watch. I primarily got it for the Oxygen sensor (O2). I’ve tried it several times now and compare the reading to several O2/Pulse meters that I already have. The readings are WAY off by 5 points or more. It is totally useless. I would send it back to Wyze, but not worth the effort. This issue plus Wyze charging me for the watch months ago has me sending all Wyze correspondence to my spam account. Very disappointed.