Whenever the description of any motor fuel subject to the rules of this Chapter is displayed on any receptacle, dispenser, or other delivery device used in its sale to the public, the type, grade, and quality of the motor fuel must be equal to or greater than the representation on the measuring device. The sign must be in one-quarter inch (1/4") to one-half inch (1/2") text letters that are easily legible from at least five feet (5').
Okla. Admin. Code § 165:15-9-1