There is a small black sticker on the back of your unit under the USB port that has a QR code. To the right of the QR code there are two rows of numbers. The bottom number is the serial number. Mine says, "17/10 114XXXX". The 114XXXX is my serial number. When you register it on the Devialet website at devialet.com/login you just put in your serial number and it will tell you what you have. Mine says, "Expert 250 Pro with core infinity.
Hope that helps.
