Purple OAMP effector with multiple control knobs. I used it with my guitar and bass. I bought it last year. It was a new item and I purchased it for over 50,000 yen. There are no particular operational issues. It's called a treatment buffer, and it's placed at the final stage of your pedalboard. The sound changes drastically, it's really good. - Color: Purple - Model Name: OAMP - Included items: Instruction manual, warranty - Controls: P, L, I, O, Gain, Lo, Hi, D, On/Off switch Thank you for viewing.