Serial numbers are typically located behind the white tag attached to the inner seam of the stuff sack, near its opening. Some products released before 2015 may not have a serial number. The Kuhli and Kuhli Pro serial number is located on the inner seam of the tarp itself. Our tote bags, storage bags, and other small accessories do not have serial numbers. Swiftlet products produced in 2020 will not have a serial number.
If you cannot locate the serial number on your product, type NA for not available as the answer to this question in the registration form. Your lifetime warranty will still be honored as long as the product is registered.