Very easy to use,
Verified Purchase(What is this?)
This review is from: Finger Pulse Oximeter With LED Display (Includes Carrycase, Batteries and Lanyard) (Personal Care)
Obviously works by timing beats over about 10 seconds, and then ratioing this up to bpm. Keeps revising this during the next half minute or so to arrive at an average over a longer period of time than the initial one. I have checked it by the conventional count and it's quite accurate. Recalibration required after 3 years, but at the price it's as cheap to buy another one.
Don't need the Oximeter but it's there as a bonus for anyone who does. You can't go far wrong by buying this.