This Aerpro control harness allows you to upgrade to an aftermarket head unit whilst maintaining use of your factory steering wheel controls. Steering controls are considered a primary harness and will require a secondary harness and patch lead to be used in conjunction for plug and play.Features: Plug and play Retains the factory Steering wheel controls The CHNIUNI has been supplied with a Bluetooth bypass plug (plug with 3 looped wires) This is only required for vehicles with factory radios that don't have an inbuilt phone button. For these vehicles the factory bluetooth module will need to be bypassed to enable phone buttons on steering wheel. Some headunits are not phone button compatible, please check functionality before installing.