I use my Roland Micro Cube guitar amp just about every day and I love it. It's the best practice guitar amp ever. Now Roland introduced the Mobile Cube for singers, keyboardists, acoustic guitar players and more. You can use a mic and any other instrument at the same time and take it anywhere using batteries. At a size that's small enough to fit in a backpack with room for your sheet music, this just seems like the perfect little practice amp for any musician, not just guitarists. From Roland: Plug into instant audio entertainment with the new MOBILE CUBE amplifier. Small and mighty, this little stereo amp can handle all types of electronic instruments and audio devices, and can be used anywhere, anytime. Connect microphones, electric and acoustic guitars, keyboards, drum machines, MP3 players, you name it, and jam for up to 15 hours.Battery-powered amplifier for anyone, anywhere, anytime5W (2.5W + 2.5W) stereo power with two high-performance 10cm (4") speakersInputs for microphone, stereo-instrument, and stereo AUX; headphone outputCenter Cancel function for karaokeBuilt-in stereo reverb/chorus, distortion and moreDedicated strap included for easy carry around