IOGEAR's Powerline Stereo Audio Adapter allows you to expand your existing Powerline Stereo Audio System. Simply plug the Powerline Stereo Audio Adapter into the electrical wall outlet to receive audio signal from the Powerline Stereo Audio System. Up to four (4) Powerline Stereo Audio Adapters can be setup to a Powerline Stereo Audio Station. IOGEAR's Powerline Stereo Audio System allows.