A diving regulator is a pressure regulator used in scuba or surface supplied diving equipment that reduces pressurized breathing gas to ambient pressure and delivers it to the diver. The gas may be air or one of a variety of specially blended breathing gases. The gas may be supplied from a diving cylinder carried by the diver (as in a scuba set) or via a hose from a compressor or a bank of cylinders on the surface (as in surface-supplied diving). A gas pressure regulator has one or more valves in series which reduce pressure from the source, and use the downstream pressure as feedback to control the delivered pressure, lowering the pressure at each stage.