The invention relates to a device for controlling the flow and/or pressure of a pressurized gas, and specifically to a tap for a pressurized-gas cylinder. The tap includes a body having a gas inlet, a gas outlet, and a passage connecting the inlet to the outlet. The tap also includes a valve for closing the passage, as well as a pressure indicator downstream from the closing valve. The pressure indicator is translatably operated and includes just two stable positions, i.e. one that corresponds to the presence of pressure, and the other to the absence of pressure.