Air compressed to 300 times atmospheric pressure - that’s over 4400 psi. Interestingly the same pressure advertised for paintball gun canisters, so probably looking at similar equipment to compress the air. Wouldn’t want to be near one when some part of the system fails.
4400 psi is just a bomb waiting to go off heh.
300 bar is the upper end for SCUBA tanks so they may be having system parts made by dive equipment suppliers. Also might have these be able to use dive shop air compressors. Hawaii might have some of those.