The speakers are connected to the subwoofer by cable. The plug is RCA, so it would be easy to extend it if the cable is too short!

"Connect your speakers via Bluetooth, micro USB or the 3.5 mm connector, or switch between the three connection modes. Even from across the room." Quote from the product page.

I guess the speakers have a battery that can be charged with the usb. But I haven't found anything specific on the website.