Voice Mini Portable Amplifier G228B CE,ROHS,ISO9001 Li-battery,With SD and USB Card,Echo ABS,it can work 8- ... 15hours continuely SD and USB Multifunctional Voice Mini Portable Amplifier with Echo Power:15W RMS/20W MaxFrequency response:100-15000HZ±3DBCurrent ... engineering plastics, it is not afraid of the impact, clear sound. 8-15 hours of continuous work, battery life can be ...