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 10 Telescopic sights for fitting to arms; periscopes, etc Commodity Code Description 90 13 10 00 Telescopic sights for fitting to arms; periscopes, etc