The Apple Watch Series 4 practical review! It has proved to be the most useful piece of tech that I have! Watch OS5 & the little hardware improvements made all the difference from last year to catch my interest to keep using it. Would make an AWESOME Christmas present!
http://www.EricaGriffin.com
  / iam_erica  
More about the heart rate sensor: https://support.apple.com/en-us/HT204666