The Aura Acoustic Imaging technology restores studio-mic'd sound to your underside or soundhole pickup.  There are 128 pre-loaded images as well as software to download images from Fishman's ever growing image gallery.  Other features include a 3-band EQ, one-knob compressor, automatic feedback suppression with up to 3 notches, chromatic tuner, effects loop, plus a high-quality balanced XLR D.I.  A genuinely versatile signal processor in a highly portable 5.6" x 5.25" x 2.1" package suitable for a wide range of acoustic stringed instruments.  Runs on 9V battery or optional AC-adaptor, 910R, not included.