Abstract: An adjustable gas flow regulator device primarily for use in medical care, said device comprising a two-part body (8/25) having a high pressure gas inlet connector (1) and a gas outlet connector (16) mounted thereon. Mounted within the body is a conventional regulator comprising a piston (9) axially movable in a stepped bore (46/47). Mounted between the output of the regulator and the outer connector (16) is a flow selector device comprising a flow selecting member (13) rotatable by means of a knob (31). The flow selecting member (13) is formed with a plurality of radially extending bores (54) in the outer part of each of which is fitted a setting plug which may be externally adjustable by a tool (not shown).