Used control board that came off a functioning furnace. See pictures for details. Buyers are responsible for purchasing the correct part and for correctly diagnosing the need for this part. If you are a Licensed HVAC Professional and you know this is the part you need – mine is an excellent choice! If you are fixing your own furnace and an HVAC Professional has not inspected your system and confirmed your need for this part, please understand you are purchasing this at your risk and not mine. If you have any questions please write and I will do my best to help.