Advent AW810 900 MHz Wireless Indoor/Outdoor Speaker System (Discontinued by Manufacturer) 900 MHz wireless technology transmits audio signals up to 300 feet through walls, floors and ceilings Dual power mode--plug in the AC adapter (included) or power it with 8 C batteries (optional) 2-way acoustic suspension design with 1" dome tweeters and 5" woofer for deep bass 15-watt Audiomax Digital Amplifier delivers impressive sound--even outdoors Water-resistant design for use outdoors and indoors in humid areas like kitchens and baths