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 15 Surveying, hydrographic, oceanographic... instruments/appliances, nes 90 15 20 Theodolites and tachymeters (tacheometers) Commodity Code Description 90 15 20 00 Theodolites and tachymeters (tacheometers)