The Yamaha NX-B02 portable Bluetooth device is a 10W stereo speaker that runs on 4 AA batteries or with the included AC adaptor. Range is 15 feet when using Bluetooth 2.0 + EDR (Enhanced Data Rate) with A2DP compatibility. There's also a 3.5 mm stereo mini jack for connecting to the speaker with a wire. Dual 1.75 inch full range speakers are 5W each and incorporate a specialized bass diaphragm to deliver deeper sound. MSRP for the NX-B02 is listed at $199.95, however we've seen prices online as low as $100.