Everything you need to know about ! 9-Volt battery powered = 12 hour playing time 2.6" 4 ohm speakers 3 Watts 1/4" Input Jack 1/4" Output Jack - allows you to daisy chain two or more amps Gain Control Knob - 10k Potentiometer Allows you to go from clear to distortion iPod, CD or MP3 player friendly with an adaptor Two sizes available: Portable is 7.5" X 4", Ultra-portable is 4.5" X 4" Output an Amp in a Can into your speaker cabinet and run your speaker cabinet off Amp in a Can's 9-Volt battery