Pneumatic controls use air as a control medium to stop or change airflow in an HVAC system. Electro-Pneumatic Transducers,Pneumatic Relays, Variable Air Volume Controllers and Pneumatic Valves create and direct the air signals used to control the HVAC system. Pneumatic Actuated Valves, Pneumatic Damper Actuators, Pneumatic Pressure Controls, and Pneumatic Electric Switches respond to changes in the air signal and create electrical connections, redirect the air signal, or open and close valves and dampers. Pneumatic Temperature Indicators and Pneumatic Temperature Transmitters respond to changes in temperature and work together to display the temperature in the HVAC system. Pneumatic controllers, Pneumatic Thermostats and Retrofit Kits, and Pneumatic VAV Control Kits respond to changes in the air signal and control the logic of the HVAC system.