Just purchased the mask thanks for the info. My plan is to have my old mask setup and this new one next time my headaches come and see what is effective. Not sure I understand why the bag would prevent o2 loss compared to my old mask which I believe had no holes so I was essentially just breathing straight 02. The more I have read the more I question my ild setup and I guess since this cycle was so different it would make sense that 02 was less effective. Life got crazy and I was not taking my vit D,traveling all over the country taking care of my dad's estate but I believe the main thing that hurt me is that I didn't have a connection for M and I need to be taking that regularly for numerous reasons.