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, PHOTOGRAGHIC, CINEMATOGRAPHIC, MEASURING, CHECKING, PRECISION, MEDICAL OR SURGICAL INSTRUMENTS AND APPARATUS; CLOCKS AND WATCHES; MUSICAL INSTRUMENTS; PARTS AND ACCESSORIES THEREOF 90 24 MACHINES AND APPLIANCES FOR TESTING THE HARDNESS, STRENGTH, Commodity Code Description 90 24 10 MACHINES AND APPLIANCES FOR TESTING METALS 90 24 80 OTHER MACHINES AND APPLIANCES FOR TESTING THE HARDNESS/STRENGTH/COMPRESS.. 90 24 90 PARTS AND ACCESSORIES OF MACHINES & APPLIANCES FOR TESTING THE HARDNESS...