This is an item for sale of the main unit only. I received this item from someone else, so I don't know much about it. I have only confirmed that it outputs sound through a USB connection to a PC, with "monitor" and "main" outputs. I haven't checked the detailed functionality, so please consider it as junk. The exterior condition is good, with no noticeable scratches or dirt. 4-channel DJ controller, USB connection, with multiple effect control knobs. - Model: KONTROL S4 - Connection Type: USB - Input Channels: 4 channels - Control Knobs: Multiple effect control knobs - Decks: 2 decks - Microphone Input: Yes - Bottom: Non-slip - Buttons: Play, Stop, Cue, etc.