A:AnswerI believe it does, yes. I’ve used it to track my sleep, and it tells me how long i slept for, how much of that was a deep sleep and other things like that so it should track the rem as well
A:AnswerThe higher the number, the newer the model. If you can still get an 8, do so and save the $$$. There were only incremental updates with the 9 and major new feature was temperature sensing that is not super accurate and is not medical grade and for predicting ovulation.
