recycled gas

[sdexcalibur]

Hey anyone ever herd of a tank that recycles the gas that you breath out and somehow let's you breath it again.
One of my buddies was telling me something about this. If this is plainly obvious or just nut. Please... be gentle

 

[nickjb]

Its called a 'rebreather'. There is a tonne of info on this site and the rest of the internet.