On Thursday, 23 January 2020 03:03:59 UTC+2, Tango Eight wrote:
Don't assume that someone else's regulator can be substituted for MH with the MH EDS.

From Mountain High's website:
"MH Oxygen Regulators are constant-pressure regulators calibrated to deliver 15 -20 psig of dynamic pressure"

Any pressure regulator supplying a constant pressure in the same range should work fine. All the fancy stuff happens in the EDS unit.

Circling back to the OP's comment about price. What is the price of one's life? $600? The same argument can be applied to a functioning parachute and an airworthy aircraft.