Section 18 Optical, photographic, cinematographic, measuring, checking, precision, medical or surgical instruments and apparatus; clocks and watches; musical instruments; parts and accessories thereof 91 Clocks and watches and parts thereof 91 07 Time switches with clock or watch movement or with synchronous motor 91 07 00 Time switches with clock or watch movement or with synchronous motor Commodity Code Description 91 07 00 00 Time switches with clock or watch movement or with synchronous motor