Powered by 900MHz Phase Loop Lock circuitry which automatically locks in and keeps the audio signal clear and strong * The system transmitter supports all types of 3.5 mm audio inputs including RCA inputs for home theater receivers, MP3 players, computers, iPod, iPhone, and iPad. * Add additional Sabrent speakers to enhance your listening experience, cover large areas or create a multi-room sound system * Charges iPodTM / iPhoneTM / USB cell phones / USB MP3 players while you listen.