AERPRO Compatible with Mercedes CLK (2005-2008), CLS W219 (2052-2011) and SLK R171 (2004-2011), the Aerpro CHMC7C steering wheel control (SWC) interface lets you retain steering wheel controls when upgrading to an aftermarket headunit. Even better, the SWC interface comes with a harness fitted with a vehicle specific plug tailored to connect directly into the wiring in place. To make the already-simple installation process much easier, throw in an Aerpro APP9 aftermarket headunit harness adapter with SWC patch lead into the mix, which will connect from the aftermarket headunit straight to the SWC interface with ease.