Every UBNT device will have a MAC ID number printed on a small sticker (or on the device itself, on some models) somewhere on the back of the device. The first 5 characters which end with a letter will be your device's Date Code. The following 12 characters, a mixture of numbers and letters, will be the MAC ID. The image to the right shows Date Code underlined in blue, and the MAC ID, in green.
Device parts will not have MAC IDs, in these cases, when filling out the RMA form, use the Serial number (S/N) in the MAC Address space in the RMA form. Date Codes will not be required for these.