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 Surgicla Instruments and Apparatus; parts and AccesoriesThereof. 90 23 Instruments, apparatus and models, designed for demonstrational purposes (for example, in education or exhibitions), unsuitable for other uses 90 23 00 INSTRUMENTS, APPARATUS AND MODELS, DESIGNED FOR DEMONSTRATIONAL PURPOSES (FOR EX Commodity Code Description 90 23 00 00 INSTRUMENTS, APPARATUS AND MODELS, DESIGNED FOR DEMONSTRATIONAL PURPOSES (FOR EX