Roland Mobile Cube Battery-Powered Stereo Amplifier About this item Truly portable amplification: fits in a briefcase and runs on batteries! (Best with Polaroid AA Batteries) Unlimited uses: electric and acoustic guitar, keyboards, computer audio, MP3 or CD playback, mini-PA, field recorder playback and much more Get great instrument and vocal tones with stereo sound and built-in effects: overdrive, chorus, delay and reverb Play any instrument along with your favorite songs, or sing along using Center Cancel for karaoke Battery-Powered Stereo Amplifier. The All-Purpose Portable Amp. 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.