Depending on the vehicle and aftermarket head unit, installation may not be completely plug and play, a small amount of hard-wiring may still be required to complete the installation. To enable steering wheel control function, this harness must be used on a compatible head unit and in conjunction with Aerpro Steering Wheel Control Interface or Infodater (sold separately). Overview Suitable for various Sony Aftermarket AV Headunits with 16 pin connectors and steering wheel control compatibility, APP9SP5 is a kit that includes an APP8 Secondary ISO Harness and Steering Wheel Control (SWC) Patch Lead. The APP8 Secondary ISO Harness converts the aftermarket head unit plug into a universal double ISO connector system, providing a simple installation solution for your aftermarket head unit into your vehicle when paired with an Aerpro Steering Wheel Control Interface or Infodapter. The Steering Wheel Control (SWC) Patch Lead simply connects between the aftermarket head unit and the Aerpro Steering Wheel Control Interface or Infodapter module, which enables your OEM steering wheel controls to work with the compatible aftermarket Sony AV Headunit.