225 ILCS 470/10
Unless otherwise provided by law, the Director may inspect and test all weights and measures held, offered, or exposed for sale to ascertain if they are correct. The Director shall, within each period of 12 months or more frequently if necessary, inspect and test all law enforcement scales used to determine vehicle weights and all weights and measures commercially used (1) in determining the weight, measurement, or count of commodities or things sold or offered or exposed for sale on the basis of weight, measure, or count or (2) in computing the basic charge or payment for services rendered on the basis of weight, measure, or count to ascertain if they are correct. However, with respect to single-service devices (meaning those designed to be used commercially only once and then discarded) and devices uniformly mass-produced, as by means of a mold or die, and not susceptible to individual adjustment, such tests may be made on representative samples of these devices. The lots of which such samples are representative shall be held to be correct or incorrect upon the basis of the results of the inspections and tests on the samples.
225 ILCS 470/10