Great for summer time when using the pool! PLug plug your MP3 Player and drop your speaker into the pool, turn it on and you done. Enjoy the outdoors with your favorite tunes. This high performance 900 MHz Wireless Speaker will allow you to transmit audio signals through walls, floors and ceilings. Compatible with MP3 players, computer, multi-media, cell phones, boom box, or home audio/video systems. Can be used with batteries (not included) or AC adapters (included). Includes one wireless speaker and a two-channel wireless transmitter. Can add up to 10 additional speakers. Range up to 150 ft., 5.0 watt RMS per channel.