The Crux SWRSU38B Radio Replacement Interface is an essential upgrade for Subaru owners who want to install an aftermarket stereo while retaining valuable factory features — especially steering wheel audio controls. Designed specifically for select 2008–2015 Subaru models, this interface module works between your vehicle’s factory wiring harness and your new head unit to maintain functions like SWC, accessory power, illumination, and more. Included in the kit are the SWRSU‑38B module, SU‑38B harness, and the 3.5 mm steering wheel control (SWC) cable, giving installers a plug‑and‑play experience with fewer splices and clean wiring. The color‑coded EIA wiring makes identifying connections simple, and the module’s pre‑programmed retention retains the original steering wheel buttons you know and use every day. Perfect for models such as the Forester, Impreza WRX, Legacy, Outback, and Crosstrek from 2008 through 2015, this interface enhances compatibility between factory systems and aftermarket radios.