The Siemens Building Technology 188-0030 Unit Mounted Thermostat is a direct-acting and reverse-acting heat/cool control device featuring a liquid-filled bulb sensor for accurate temperature response. Designed for unit ventilators, fan coil units, and other HVAC terminal equipment, it regulates heating and cooling output by responding to temperature changes and modulating system opera... https://www.partshnc.com/th188hc-unit-mtd-t-stat