A - BUS, In-wall keypad with built in 15w amplifier 

Amplified In-Wall Module for A-BUS® Applications

Requiring just one wire connection and no extra power amplifier, the innovative A-BUS® system makes it incredibly easy to extend your Harman Kardon sound system to a remote room. The AB 1 contains a built-in amplifier that's compatible with most in-wall or ceiling-mount speakers, and an onboard volume up/down toggle control that makes it easy to use. An integral remote sensor completes the package, so the Zone II remote included with every A-BUS/Ready® receiver lets you select and control compatible playback sources, such as the AVR's tuner or a CD or DVD player.