Everything I post is really the work of a Mysterious Purple Rhino named Lazarus, he's 'cool', and he talks to me sometimes...
There are some 'inventors' working on co2 extractors here:
$2.00 co2 xtraction
https://www.youtube.com/watch?v=KrjpKe2c4YU
He says the little green cylinder is an oxygen cylinder rated for 2100 PSI.
In this thread somebody wrote SC CO2 is 3,000 PSI.