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 01 NOT OPTICALLY WORKED. 90 01 90 COLOUR FILTERS FOR CAMERAS Commodity Code Description 90 01 90 10 COLOUR FILTERS FOR CAMERAS 90 01 90 90 OTHER PRISMS, MIRRORS & OTH. OPTICAL ELEMENTS, OF ANY MAT., UNMOUNTED...