The pad ID number lets our team know when the pad was created, down to the month, which helps improve our Quality assurance. This number is printed on the weld on the top of the pad near the valve for both Laylow valves and pre-2019 "Stem" valves. Here are some photos of a Tensor and where to locate that weld. but it is the in the same location for all of our sleeping pads.
It will look something like 60TWN1902. If you're still having trouble finding it, no problem! Feel free to leave that section blank.