Is there a mask that you recommend/ know of that would allow me to keep eyes uncovered
You can probably spray paint the visor of a mask or put another bag on top of an eebd hood ?
Obviously that means that the bag is not creating a complexity airtight seal. Here's my confusion: If an exit bag is the "ideal" set up for the inert gas method, and it is not completely air tight by design, then what difference would it make if a mask was not completely air tight
Exit bag: with oxygen in your body your create CO2 while breathing. A high concentration of CO2 wile result in air hunger and the panic of suffocation.
The CO2 is purged through the bottom of the bag.
Positive pressure mask: Inside the mask the pressure is higher than the ambient pressure. The advantage is that the mask sucks to your face
when it's fixed correctly and creates a perfect seal. You will also only use gas when you breathe. If that seal is however broken you will loose
a lot of gas in a short time and it might not be able to be enough to ctb.
Negative pressure masks: Require you to place them correctly on your face to achieve seal. You will also use more gas when the fit is not perfect
but far far far less then with a positive pressure mask. You will also get fresh oxygen into your mask which could delay ctb or make it not work at all.
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@GasMonkey said Carbon monoxide is different so you cant compare it. Look it up on wikipedia but the gist, carbon monoxide docks onto your
red blood cells like oxygen would. Leaving less and less blood cells left until you faint and die. It's a poisoning on the blood level of your body.