An acoustic effector with versatile tone adjustment. Although not expensive, it sounds better than its price. It can be powered by both an AC adapter and batteries, so you're covered even without an outlet or if the AC adapter breaks! It's a user-friendly preamp. Operation confirmed with AC adapter and batteries. There are no noticeable scratches, but the barcode sticker on the back is slightly torn. Instruction manual included. Batteries for operation check are also included. Thank you. - Model Name: ACOUSTIC ADI 21 - Brand: behringer - Function: Acoustic Modeler - Controls: TREBLE, MID, BASS, LEVEL, MID FREQ, BLEND - Connections: Input Jack - Features: PAD, GND LIFT switch Thank you for viewing.