A device for controlling the flow of gas from a gas container, comprising a gas flow passageway through said device and having an inlet and an outlet, wherein the inlet is configured to be sealingly attached to a gas container to receive gas from the gas container; gas flow control comprising a valve in said passageway capable of controllably closing or opening the passageway to the flow of gas therethrough, and a manually operable selector exterior to said device and operatively connected to said valve to enable adjustment of the position of said valve to a closed position and one or more open positions by movement of said selector; a pressure sensor capable of detecting the pressure of gas in a container when the device is sealingly attached to said container and of generating an electronic signal corresponding to the detected pressure; an electronic display capable of displaying information in digital and/or analog form (37, 39); an electronic alarm capable of being actuated to signify the presence of an alarm state audibly, visibly, or both audibly and visibly; and an electronic control connected to said gas flow control, said pressure sensor, said display, and said alarm, characterized in that the electronic control is capable of detecting the position setting of said valve, detecting from said pressure sensor at periodic predetermined time frequencies the pressure of gas in said container, calculating as a function of said detected position setting and said detected periodic pressures the interval of time remaining until the amount of gas in the container will reach a predetermined lower threshold, generating a signal causing said display to display said interval, and generating a signal actuating said alarm when the amount of gas in the container reaches said predetermined lower threshold the manually operable selector is rotatable the electronic control is configured to temporarily deactivate said electronic alarm through a rotation of the manually operable selector to a predetermined position such that the contents of the gas container can be exhausted without activation of the electronic alarm; and the electronic control is further configured to initialize the electronic alarm from a deactivated state when the pressure sensor detects the pressure of gas in the container as exceeding a predetermined upper threshold to allow further activation of the electronic alarm. a gas flow passageway through said device and having an inlet and an outlet, wherein the inlet is configured to be sealingly attached to a gas container to receive gas from the gas container; gas flow control comprising a valve in said passageway capable of controllably closing or opening the passageway to the flow of gas therethrough, and a manually operable selector exterior to said device and operatively connected to said valve to enable adjustment of the position of said valve to a closed position and one or more open positions by movement of said selector; a pressure sensor capable of detecting the pressure of gas in a container when the device is sealingly attached to said container and of generating an electronic signal corresponding to the detected pressure; an electronic display capable of displaying information in digital and/or analog form (37, 39); an electronic alarm capable of being actuated to signify the presence of an alarm state audibly, visibly, or both audibly and visibly; and an electronic control connected to said gas flow control, said pressure sensor, said display, and said alarm, characterized in that the electronic control is capable of detecting the position setting of said valve, detecting from said pressure sensor at periodic predetermined time frequencies the pressure of gas in said container, calculating as a function of said detected position setting and said detected periodic pressures the interval of time remaining until the amount of gas in the container will reach a predetermined lower threshold, generating a signal causing said display to display said interval, and generating a signal actuating said alarm when the amount of gas in the container reaches said predetermined lower threshold the manually operable selector is rotatable the electronic control is configured to temporarily deactivate said electronic alarm through a rotation of the manually operable selector to a predetermined position such that the contents of the gas container can be exhausted without activation of the electronic alarm; and the electronic control is further configured to initialize the electronic alarm from a deactivated state when the pressure sensor detects the pressure of gas in the container as exceeding a predetermined upper threshold to allow further activation of the electronic alarm.