A:Answer Hi papa42,
1. To use the speaker add function, two GTK-XB60 or two GTK-XB90 systems are required.
2. The Maximum communication range of Bluetooth 10 m (33 feet - Line of sight approx.)
3. You need to plug it in to power outlet directly for power.
Reference: https://www.sony.com/electronics/support/audio-systems-gtk-series/gtk-xb60
Regards,
David