Bluetooth speaker portable speaker outdoor speaker power rating 15 watt effective output 15 watt speaker system 20 stereo principle active frequency response 75 20000 hz amplifier type digital power supplies rechargeable battery usb battery life 12 h charge time 4 hrs type of battery lithium ion battery capacity 6 000 mah charging port micro usb colour black front colour black functions bluetooth multipoint speakerphone function smartphone ch