Easy set up with Bluetooth and completely wireless. Pair with any Bluetooth-enabled device to one and run up to 99 of the same speakers all playing the same music. Fully self-contained internal rechargeable battery with both solar or USB recharge options. Features: - Long-range CSR Bluetooth v5.0 for extended-range connection to and from your mobile device - Multi-Link NEXUS Function enables up to 99 of the same speakers to connect and play at the same time - Completely wireless operation with easy setup and installation. Users no longer need to be tied down to indoor amplified sound that needs to wire to passive outdoor speakers to control outside music - Built-in rechargeable Lithium-Ion batteries operate speakers for up to 10 hours on a full charge - Solar and USB charging options No wiring required. Solar option charges both on sunny and cloudy days