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 21 HEARING AIDS AND OTHER APPLIANCES WHICH ARE WORN OR CARRIED OR IMPLANTED 90 21 31 ARTIFICIAL JOINTS 90 21 31 00 ARTIFICIAL JOINTS Commodity Code Description 90 21 31 00 000 ARTIFICIAL JOINTS