Uniweld RO Patriot series oxygen regulator has an "A" outlet connection and a 540 CGA (Compressed Gas Association) inlet. The Patriot series regulators feature protective rubber gauge boots, rear inlet service and the specially compounded diaphragm and seat material that provide accuracy and reliability. The regulator provides a delivery pressure of 2-60 psi. It comes with a 100 psi delivery gauge and a 4000 psi contents gauge. Replacement delivery gauge is Part # G49D. Replacement contents gauge is Part # G56D.