The Aerpro CHMC8C Steering Wheel Control Interface (SWC) allows you to upgrade to an aftermarket headunit whilst maintaining use of your factory steering wheel controls. Engineered to suit various Mercedes models with MOST 25 Fibre Optic Amplified Systems, the steering wheel control interface includes a harness that is fitted with a vehicle specific plug designed to connect directly into the existing wiring in the vehicle with ease, no cutting of the factory wiring harness in the vehicle is required. Installation of the aftermarket headunit is simplified even further when paired with the optional Aerpro APP9 Headunit Secondary ISO Harness & SWC Patch Lead, which connects between the aftermarket headunit and the Aerpro Steering Wheel Control Interface. This interface is CANBUS & Fibre Optic compatible and provides various outputs including Reverse Trigger, Park Brake, Speed Pulse and Illumination.