Audio Unlimited SPK-TRANS Wireless 900Mhz Transmitter 1 Pack Fully compatible with all Audio Unlimited products Create a multi-room sound system Phase Loop Lock circuitry automatically locks in and keeps audio signal clear and strong Connect to your computer for remote listening 900 MHz transmitter sends audio signals without speaker wire Transmitter connects via 3.5mm audio cable to PCs, MP3 players, iPods, stereos and home theatre systems