Good information to know, and logical. Out of curiosity we might throw the adult one on him just to see what the numbers are (if it will even give a reading on his little fingers), and understand not to take much stock in the numbers. Sound, practical advice from the good doctor... as always. I'll just not bother buying a specific child POX. As I said, we're not intended on hitting oxygen levels anyway, but do have the appropriate equipment. If we hit the practical limit above, we're descending or landing anyway.