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 32 Automatic regulating or controlling instruments and apparatus. 90 32 10 Thermostats Commodity Code Description 90 32 10 00 Thermostats