225 ILCS 470/39
Inspectors of weights and measures of this State may seal, for use in trade or commerce, all weights and measures and weighing and measuring devices, the type of which has been approved as required by the provisions of this Act, or specifically exempted from the necessity of approval by the provisions of this Act, when they find that the same are within the tolerance prescribed under the rules and regulations. This Section does not permit approval of a type to be deemed evidence of the correctness of any individual weight or measure or weighing or measuring device of that type, or prevent any such inspector of weights and measures from prohibiting the use of any individual weight or measure or weighing or measuring device that is found to be inaccurate or otherwise defective or unlawfully used and enforcing any penalty provided by this Act.
225 ILCS 470/39