Roland DEP-3 digital effector, a professional-grade unit with a block diagram of its internal structure and input/output terminals. I confirmed the reverb effect and the changes in sound when turning each parameter knob. There was no scratchiness in any of the knobs. There are scratches on the top surface. - Brand: Roland - Model: DEP-3 - Color: Black - Function: Digital Effector - Connection Terminals: Input/Output terminals available - Block Diagram: Displays the internal structure's block diagram Thank you for viewing.