Abstract: An oxygen pressure regulating device (100) is disclosed. The device (100) comprises a housing (102) including an inlet port (104) and an outlet port (106), the housing (102) including: a spring unit (112) including a plate (116) placed in fluid communication with the inlet port (104), the plate (116) being configured to be moved when impinged upon by an oxygen stream at a first pressure received through the inlet port (104); a bellows arrangement (118); and a switch (146) configured to be activated to open the outlet port (106) for releasing the oxygen stream through the outlet port (106). Also disclosed is a system comprising the oxygen pressure regulating device (100), a laminar flow element and a second conduit.