Boss ME-20B Bass Multi-Effects Performance-based bass processor for the player who wants an easy-to-use interface with BOSS tone and quality New super-tough metal chassis with 3 footswitches, 5 realtime control knobs, and expression pedal EZ Edit for quick sound creation Unique effects such as Synth, Octave, Defretter, and more BASS ENHANCE function for instant presence boost 30 user memory locations in addition to realtime operation Battery or AC powered