Dinosaur Elect. TDR Time Delay Relay for 12V FurnacesThis is a replacement time delay relay for use in older furnaces that use a standard 12VDC ignitor board. the TDR has a 4 second delay before applying power to the fan motor, and a 2 minute cool down period at the end of the heat cycle before removing power from the fan motor. This unit measures 1-1/2″ x 1-1/2″.Electrical Component (Non-Returnable)Please keep in mind this is an electrical component, per Panther RV Products return policy, this product is non-returnable.