Okla. Stat. tit. 59, § 59-1820.10: Service work tag required

Any person who services, installs, inspects, certifies, charges

or tests any portable fire extinguisher or fire suppression system

shall affix a tag to the service unit. The tag shall indicate the

date upon which the service work was performed, and it shall bear

the legible signature and state license number of the person and

other information specified by the State Fire Marshal Commission.