This is a compressor that can produce a distinct "paco-paco" sound emphasizing attack, or be used subtly as a flavor enhancer. I remember being amazed at the price when I bought it! I used it when I went back to my parents' house, but I'm selling it due to changes in my living situation. The box and instruction manual are included. I will clean it again before shipping, but I am not a professional, so please refrain from purchasing if you are overly concerned about its condition. There are various videos on YouTube, so I recommend watching them before you buy.