CGA-540 2-stage 4-Port regulator.
The Dual Stage regulator allows the useful pressure of a cylinder
to be spent down to about 10 psi above the regulating pressure.
This will still yield the specified flow rate for the application while
maintaining specified pressure and flow requirements.
This 4-port regulator incorporates the snap-in (CPC) style fittings.
Click on the link below to learn more about 2-Stage regulators.
https://www.mhoxygen.com/2016/download/855/regulators/27404/dual-stage-reg-109x-data-sheet.pdf
