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 13 Lasers, other than laser diodes; other optical appliances and instrume nts, not specified or included elsewhere in this Chapter. 90 13 20 Lasers, other than laser diodes Commodity Code Description 90 13 20 00 Lasers, other than laser diodes