Abstract: The continuous NITROX mixer is a pre-calibrated, continuous flow, gas mix system and a method which combines pure oxygen and air at atmospheric pressure, to create a final mixture of predetermined composition. Constituent gases are regulated to the same pressure and temperature before oxygen is metered through precision micro-metering valves. The system proportions the amounts of each gas and delivers the final mixture to a common mixing chamber. Delivery pressure can be adjusted up to 3000 PSI, making the system suitable for filling SCUBA or storage cylinders.