Section 18 OPTICAL, PHOTOGRAPHIC, CINEMATOGRAPHIC, MEASURING, CHECKING, PRECISION , MEDICAL OR SURGICAL INSTRUMENTS AND APPARATUS; CLOCKS AND WATCHES; M USICAL INSTRUMENTS; PARTS AND ACCESSORIES THEREOF 90 Optical, photographic, cinematographic measuring, checking, precision, medical o 90 31 Measuring or checking instruments, appliances and machines, not specified or inc 90 31 10 90 31 10 00 Commodity Code Description 90 31 10 00 00 - Machines for balancing mechanical parts