Guitar amp modeler that achieves a variety of tones. Power-on and sound output were confirmed, and everything worked normally. Since it was tested with a 9V adapter, battery operation has not been confirmed. Please forgive minor scratches and dirt as it is a used item. No box or manual. - Model Name: GUITAR GDI 21 - Brand: BEHRINGER - Color: Blue - Function: Guitar amp modeler/driver - Controls: Drive, Treble, Bass, Level - Connections: 1/4 inch jack - Features: GND lift switch, AMP mode switch Thank you for viewing.