Excalibur SoundMaster Wireless Speakers 157BK EXCALIBUR 157BK SoundMaster Satellite Wireless Speakers with Universal Dock for iPod. Bask in the freedom of enjoying your music where you want it, when you want it, without the need for an annoying bundle of unsightly wires. The new SoundMaster AirFree combines the latest in wireless technology with rechargeable speakers that can be placed anywhere in your home or office. You are free to listen to your favorite music, transmitted interferencefree, wirelessly, from any iPod or iPhone. Each wireless speaker has its own amplifier and builtin rechargeable battery. Lift the speaker from the charging base and put it anywhere, its easy. When the speaker sphere is returned to its base, the wireless function automatically shuts off, and the speaker will begin to charge. Each speaker offers a full 6 watts of power. 915 MhZ wireless signal ensures clean, clear music up to 120 feet away, without interference.