Siemens 192-841 Pneumatic Retrostat Reverse Acting Single Temperature is a machine to control temperature in HVAC systems. The single setpoint display makes this pneumatic retrostat for applications where a precise temperature control is required. It is constructed from durable plastic in a classic white color and blends in with many environments. #Siemens #192-841 #PneumaticRetros... https://www.partshnc.com/retrostat-ra-single-temp