Well damnit! I was all keyed up to get a 72 hour reading at work but forgot my meter there. So it will sit there for the weekend. Perhaps I'll start another experiment next week.

Even how you blow into it is variable I can produce a higher reading by simple breathing near the open mouth piece before putting my lips to it and giving it a good go.

I see the usefulness of this device just to show simple trends if the user has a consistent practice.

Bottom line, this thing is more about entertainment value than research but fugg, it's kind of FUN.