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, medical or surgical instruments and apparatus; parts and accessories thereof 90 28 Gas, liquid or electricity supply or production meters, including calibrating meters therefor. 90 28 30 Electricity meters Commodity Code Description 90 28 30 00 Electricity meters