Thank you all for your comments in this forum. I discovered it recently and it is being really helpful. I am totally determined, and I am just purchasing the last details and trying to decide between the bag or the mask. Regarding the bag, I have a question... I hope this does not sound stupid, but I cannot find an answer:
If the bag needs to be loose around the neck for the CO2 to be expelled... wouldn't a little amount of O2 go inside the bag as well?
Also, how loose does it needs to be? I understand it is important to have some "room" for the CO2 to go out and for the bag not to explode, right? But I am afraid of making it too loose.
Thanks a lot!