Mich. Comp. Laws § 290.619: City and county official standards; comparison with state standards.

Sec. 19.

Standards of weights and measures provided by a city or county, after examination and approval by the director, shall be the official standards for such city or county. The sealer shall make, or arrange to have made, at least as frequently as once in 5 years, comparisons between his standards and appropriate standards of a higher order belonging to the state in order to maintain such standards in accurate condition.