oxygen bottles?
Question: in the ER, we use the big tanks (without sympathy to 5 feet high) for a principal use, then we have two small (ish) tanks up to be transported.
Answer: Judgement. The pressure is just pressure, that does not cover the volume. You may have a reduced to ten cubic feet cubic inches to 170 atmospheres (or 3000 psi), but is still a cubic foot of oxygen.

been dispatched to the climax of Mt Everest to clear the summit of plastic detritus as well as abandoned tents, oxygen cylinders, sleeping bags, tin cans....










