The programmable gas mixer carries up to three inlet gases and produces user-defined mixtures using these gases. A mixing program can be set and stored at any time without the use of the software. This mixture is stored in non-volatile memory so that it does not need to be reintroduced the next time the instrument is used. The equipment uses high-precision mass flow controllers (calibrated for each gas) to define the flow programmed by the user. Each mixture is defined by a Total Flow and the percentage concentration of each gas in the mixture. The resulting flow for each gas, in cubic centimeters per minute, is calculated and displayed on the LCD display.