This chest pack ventilation control module was designed to be used by astronaut Edward White during the Gemini IV mission.
The chest pack was the central component of the Extra-vehicular Life Support System (ELSS). It supplied oxygen from the spacecraft umbilical or from the backpack at normal rates of 5.1 or 7.8 lbs per hour. This supply was mixed with the secondary ventilation gas, and was then supplied to the suit for cooling and CO2 wash-out.
NASA transferred this to the museum after the end of the Gemini program.
This object is on display in Destination Moon at the National Air and Space Museum in Washington, DC.