This speaker can be expanded up to 6 speakers. You can also add a wireless headphone to the system. You can plug any audio device that has a 3.5 mm headset port directly into the unit for easy plug and play. When you use the transmitter you can charge you iPod or MP3 player through the built in USB Port . The product is water resistant so it is great around the pool. You can plug your cd player, iPod, mp3 player, receiver, cable box, etc.

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