From the manufacturer
Wireless Bluetooth Streaming
Wirelessly connect up to 2 smartphones or tablets to the speaker and take turns enjoying powerful sound.
Up to 20 hours of playtime
Built-in rechargeable Li-ion 7500mAH battery supports up to 20 hours of playtime and charges your device via USB port.
Take Charge 4 to the beach or the pool without worrying about spills or even submersion in water.