California Code, Business and Professions Code - BPC § 12511

Any weight, measure, or weighing or measuring instrument tested and found correct by any sealer may be used within this state without any further test for such period as is authorized in the regulations adopted by the secretary pursuant to Section 12212.  If tested and sealed and certified to as correct by the National Institute of Standards and Technology, any weight, measure, or weighing or measuring instrument may be sold without being first tested and sealed by a sealer.  In either case, it shall be subject to inspection and testing notwithstanding that it has been tested and sealed either by a sealer or by the National Institute of Standards and Technology.