The Yamaha DD55C 7 Pad General MIDI Digital Drum System is a serious musical instrument to extend the creative latitudes of a professional or amateur drummer. It works on batteries or an optional PA5D AC adapter. 100 Built-in Rhythm Styles for accompaniment 50 Programmed Drum Kits One User Programmable Drum Kit to store a favorite setup Reverb and Chorus Effects Large 3-Digit LED display screen General MIDI and MIDI In/Out for computer connectivity Headphone Jack Stereo Speakers with Bass Port and 5 Watt per channel amplification deliver exceptional sound Port for hookup to an external amplifier Download songs from Internet and play them Includes 2 Drum Sticks Battery requirement information not available at writing