A pressure regulator comprising a housing having an inlet in communication with a gas source, an outlet operable to supply a gas at a given pressure and flow rate, a conduit extending between the inlet and the outlet, a restriction device located in the conduit and positionable to control the flow of gas therethrough, a biasing arrangement to apply a predetermined bias to the restriction device and a selection device operable to select one of a predetermined plurality of discrete, offset configurations of the biasing arrangement and restriction device to provide a discrete selection of gas pressures at said outlet. The outlet comprises a fixed-size orifice selected from a specific group of fixed-sized orifices such that the combination of orifice and selectable position of said selection device provide a group of discrete flow rate/pressure combinations to applications downstream of said outlet.