NATIVE Instruments MASCHINE MK3 ・I purchased this used previously, but I didn't quite understand how to use it. I've also concluded that a MIDI keyboard suits my needs, so I've kept it stored away. This is a short set, including only the USB cable (which can connect to a PC) and the main unit. The serial number is affixed to the back of the unit, and no paper with serial numbers for other software, etc., is included. ・I confirmed that it powers on, the LCD lights up, and it boots up when connected to a PC via USB cable. However, as I am a beginner, I couldn't figure out how to connect it to a DAW or make any sounds. Therefore, I haven't been able to confirm its functionality by actually playing or recording. Please understand and agree that the functionality has only been "power-on confirmed" before making a purchase. It is assumed that the previous user or someone else possesses the transfer ID and other serial numbers besides the one on the back of the unit, so I cannot provide any support regarding those. I recommend this product to those who are familiar with and understand the handling of used serial numbers for NATIVE Instruments products.