Featuring a convenient, contemporary, and portable design, Acoustic Research AW825 Outdoor Wireless Speaker delivers crisp, high-quality sound. It could be powered using the bundled AC adapter or 6 AA batteries and is compatible with both iPod and iPhone. The portable wireless speaker allows you to choose from three broadcast frequencies. Equipped with a two-way speaker design, the weather-resistant drivers deliver 5W RMS power and reproduce most frequencies from the response range with exceptional clarity. The 3-inch mid-bass driver and the 2-inch horn-loaded tweeter do a neat job in their corresponding ranges. Crafted with auto-lock PLL tuning, the iPod wireless speaker facilitates clear reception up to 150 feet. Also, the iPhone wireless speaker could be expanded with multiple units.