The NUX AC-25 is a compact acoustic amplifier with built-in rechargeable battery that can run four hours for busking, mobile performance and impromptu gigs. It equips a 6.5" speaker, modeling preamps, reverb, Bluetooth audio streaming and a drum machine. You can tweak it through the Stageman app on the mobile phone. The dual channel configuration means you can plug a dynamic mic and your acoustic guitar. You can play playbacks via Bluetooth or auxiliary input.