A compact, regulated gas flow control valve includes a valve body having a clamp for securement to a high pressure gas cylinder. An inlet at one end receives the high pressure gas from the cylinder. A piston-actuated regulator drops the high pressure to a low pressure, maintaining the low pressure at a substantially constant delivery value. An outlet and a flow control selector knob are located at the other end of the valve body. The knob selects a preselected flow rate for delivery of the low pressure gas by the outlet. The knob controls position of a rotor carrying a plurality or precalibrated flow control orifice inserts, the knob being rotatable but with positive detenting for orienting the rotor to permit flow only through a selected one of the orifice inserts for delivery by said outlet. The sequence of orifice inserts defines a preselected schedule of different flow rates upon rotation of the said selector knob.