Section 18 Optical, photographic, cinematographic, measuring, checking, precision, medical or surgical instruments and apparatus; clocks and watches; musical instruments; parts and accessories thereof 90 Optical, photographic, cinematographic, measuring, checking, precision, me Thereof. 90 28 Gas, liquid or electricity supply or production meters, including calibrating meters therefor 90 28 10 - Gas meters Commodity Code Description 90 28 10 00 - Gas meters