Review on IProven Pulse Oximeter: Accurate Blood Saturation And Heart Rate Monitor With Batteries, Case & Lanyard - OXI-27Black (Black/Red) by Scott Welch

It works. I bought this to see if it would go off while I'm sleeping because I have a snoring problem but it turns out that I cant sleep with it on for two reasons. It wont stay on my finger while falling asleep and while it is on it wont stop beeping. The ideal oxygen level ranges from 95 to 100%. Between this range it wont go off but that can drop if your activity level drops. At 93% it beeps constantly which is where I'm at when laying down and trying to go to sleep so if this is why you are buying it this may not work for you. They should have designed the alarm to go off below 90% which is really where it should be if you actually have an oxygen problem. I also bought this hoping it would be able to track alarms but it doesnt appear to do that. I was also disappointed that amazon delivered it a day late (again) but I did not take any stars off for this because that is an amazon issue not a product issue and I'll save that for a prime review later.