This oximeter works really well for both testing blood saturation levels an pulse reader. I tried using this with the heath app I have and it worked well at tracking trends. I was able to see levels throughout the course of sleeping and that information was incredibly interesting.
It is really easy to use and I like that it comes with an infant strap as well as a carrying bag. I am very satisfied with it!

While this oximeter seems a bit pricey, it does do it's job well. It's nice that the batteries are included, and it has the infant attachment to use with babies and small children. Plus, results are easily tracked in the phone app.