The PMX-HD9813 source unit utilizes the factory wiring and therefore wiring harnesses are not supplied. Harnesses are sold as a pair. We are providing these replacement harnesses for instances such as:- Dealers with product demo displays - Customers with aftermarket radios where the OEM plug(s) have been cut-off.- Customers adding rear speakers to a motortcycle that did not have rear speakers.The SMALL connector harness contains power, ground, ACC, illumination, and front speaker outputs.The LARGE connector harness contains rear speaker outputs.