Acoustic Research AW877 900 Mhz Indoor Wireless Speakers (Black) (Discontinued by Manufacturer) Wireless indoor speaker has up to 250 foot range Built in carrying handle for easy portability room to room Automatic level control avoids sudden changes in volume while 2 way acoustic design provides high quality omni directional sound Convenient push button auto lock phase lock loop tuning locks onto transmitter signal and guarantees clear audio Dual power mode with AC adapters supplied -batteries optional