N.C. Gen. Stat. § 81A-73
Whenever any service is rendered on any scale or weighing device used or intended to be used in this State by a scale technician, a certificate shall be issued by such scale technician who rendered said service, which shall be known as a "service certificate." The size and form of said service certificate shall be determined by the Commissioner or his authorized agent. Inclusive of other pertinent information or statements, the said certificate shall bear a statement expressed in ink or other indelible substance naming the kind of service rendered, whether adjustment, installation, repair, or maintenance, and stating that a service test as defined under the term "service" has been made, and that the service rendered is guaranteed to be as represented. The service certificate shall be made out in triplicate, with original going to the owner of such scale of weighing device or his agent, and a duplicate shall be sent to the Commissioner or his authorized agent and the triplicate copy shall be retained by the scale technician issuing such certificate.
N.C. Gen. Stat. § 81A-73