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 29 Revolution counters, etc; speedometers and tachometers; strobescopes 90 29 20 Speed indicators and tachometers; stroboscopes Commodity Code Description 90 29 20 00 Speed indicators and tachometers; stroboscopes