The BOSS RDD-10, a micro rack effect unit equipped with delay and modulation effects, is perfect for guitar and keyboard recordings. I have confirmed the delay and modulation effects. I have confirmed that the effect changes depending on the changes in each knob. There was no scratchiness in any of the knobs. Includes a genuine BOSS AC adapter. Although there is some dirt and rust on the exterior, there appears to be no damage internally. It is currently working, but due to the age of the equipment, it is sold as-is, with no returns accepted. - Model Name: RDD-10 - Brand: BOSS - Series: MICRO RACK SERIES - Block Diagram: Block diagram displayed - Input/Output Terminals: Multiple input/output terminals (1/4 inch phone jacks, RCA jacks) - Effect Type: Delay, Modulation - Power: 9V AC adapter BOSS PSA-100 included Thank you for viewing.