The Johnson Controls T-4002-202 Pneumatic Thermostat Reverse Acting Horizontal is designed to provide precise temperature control in HVAC systems. This is a reverse-acting thermostat, meaning that while the temperature rises, the air pressure in the control line drops. By modulating the associated HVAC system, this process maintains precise and consistent room temperatures between 55°... https://www.partshnc.com/pneumatic-tstatrahorz