... bettery usageOuput power: 20 W, clear and nice loud voice, good penetration. Power output: 20W Charger voltage: 12V 1800mAh Product weight ... .Music amplifier :When connect the computer or MP3 with the cable , the music volume could amplified by this mini amplifier box ... like more function, I will recommend you as your request . Good price! Portable microphone with USB for teachig, meeting, restaurant