BOSS Digital Delay DD-2, an effects unit with stereo output and mono input. It can also hold sounds. It's an old item. - Model Name: Digital Delay DD-2 - Brand: BOSS - Output Type: Stereo Output - Input Type: Mono Input - Control Knobs: 4 knobs (MIN/MAX settings) - Condition: Shows signs of use (scratches and dirt) Thank you for looking.