A Direct Acting Pneumatic Thermostat is a temperature control device that regulates temperatures within a building. It works by monitoring the temperature in the area, then uses pneumatic components to automatically adjust the target temperature until a desired temperature is achieved. The thermostat operates on air pressure signals generated by air-controlled switches working together with an actuator or other pneumatic valves. This makes it ideal for controlling temperatures in commercial or industrial buildings, where precise temperature control and stability are of utmost importance for safety, efficiency, and comfort.