Sabrent Weather Resistant 900MHz Wireless Indoor/Outdoor 150 FT 2 Speaker System with Remote and Dual Power Transmitter (SP-ESKY) 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 iPod / iPhone / USB cell phones / USB MP3 players while you listen.