Section 18 OPTICAL, PHOTOGRAPHIC, CINEMATOGRAPHIC, MEASURING, CHECKING, PRECISION , MEDICAL OR SURGICAL INSTRUMENTS AND APPARATUS; CLOCKS AND WATCHES; M USICAL 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 Commodity Code Description 91 07 00 00