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Are you using it for diving or for emergency O2? There are a number of breathing certified O2 types available. I don't know if I'd call them higher or not as high, they just have different specs. You are correct, ABO has a smaller allowable dewpoint than Medical. Diver grade can be filled on a welding rack as long as the pressure in the cylinder never goes below 500 PSI. Diver grade is a Praxair mix of 99.5% O2. It is a breathing air grade. There isn't a spec for the other .5%, I hope it isn't CO.