The Trane SEN0355 Flame Sensor is a genuine OEM safety component designed to verify the presence of a burner flame in HVAC heating systems. It works by detecting the flame through flame rectification technology and sending a signal to the furnace control board, allowing the gas valve to remain open only when a stable flame is present. Commonly used in Trane and compatible gas furnaces... https://www.partshnc.com/flame-sensor-180