Oxitracker works fine!!! Takes a little patience but it's worth the time. First, this is Oxitracker you want for the M70C Pulse Oximeter. When you first open Oxitracker , go to the "Registered" block and click it. It shouldn't have the "ed" at the end of the word and it would be less confusing!! Oxitracker will open up and you can Register. It will e-mail you and when you open that e-mail, it appears to "activate" your Account. You then go in and enter your data, weight, height etc. OR NOT since it doesn't use this data for any calculations that I could see? But you can at least enter your first name and then any other "Family Members". If you touch one of these Names, i.e. Your Name or a Family Member, Oxitracker starts looking for your Pulse Device. Simply touch the start button on your Pulse Device and put your finger in the Pulse Oximeter and you can watch your heartbeat and all your stats on your phone. This is logged in Oxitracker and creates graphs that track your Stats over time, pretty slick. So contrary to the first 5 Reviews, Oxitracker works well and does exactly what most of us would it expect it to do!!! I'd have given it 5-Stars had the implementation been a little more intuitive but it's definitely 4-Stars or Better!!