Wis. Stat. § 213.15: Fire hose threads and fittings to be uniform.

All fire hose fittings, apparatus fittings, 1.5 and 2.5 inches in diameter purchased or procured by a fire department or fire company shall be of the national standard hose thread as adopted by the national fire protection association. No fire department shall utilize hose and equipment not in conformance with the requirement that all threads shall be national standard hose thread as adopted by the National Fire Protection Association. Any person offering for sale nonstandard hose couplings, fittings or apparatus fittings may be fined not less than $100 nor more than $500.