... convenient and environmental*Connect computer with USB data link, used as speaker*Built-in 3.5' high power speaker, ... adapter specification:DC 10V / 450mA*Battery specification:2pcs 3.7V/1100mAh lithium-ion Battery*Play time:8-20hrs ... , Morning exercise, Training, Sports, Speech,Publication,Outdoor entertainment 2012 Professional Multifunction 18W Portable Voice Amplifier With Headset Microphone V-8