The Reznor 271994 Averaging Temperature Sensor, 36" Yd B, is designed to provide accurate temperature readings by averaging air temperatures across ducts in HVAC systems. Commonly used in Reznor heating and ventilation equipment, it helps maintain consistent climate control by sending precise data to the system’s controller. https://www.partshnc.com/271994-reznor-averaging-temp-sensor-36--yd-b