Business and Professions Code § 12303

The state standards of weights and measures by which all state and county standards of weights and measures shall be tried, proved, and sealed include the following standards, provided the standards have been certified relative to national standards under the direction of the National Institute of Standards and Technology:

(a) Metrological standards provided by the United States.

(b) Metrological standards procured by the state.

(c) Metrological standards in the possession of county sealers.

(d) Metrological standards in the possession of laboratories certified to perform measurement services pursuant to Section 12314.