MusicCAST In-Wall music distribution package (includes MCX-C15 and MCX-CA15), The MCX-C15 In-wall Client is a compact design – Fits low-voltage dual-gang box with 4 Assignable Favorite direct buttons on controller and remote - will allow user to preset to Artist, Album, Genre, Playlists or inputs. While the MCX-CA15 in-wall mountable amplifier is a Multi-purpose, stand alone Power Amplifier package (includes MCX-CA15 and Power Supply), and is a perfect match for the MCX-C15 in-wall controller.