90019090 under HS Code OPTICAL FIBRES AND OPTICAL FIBRE BUNDLES; OPTICAL FIBRE CABLES OTHER THAN THOSE OF HEADING 8544; SHEETS AND PLATES OF POLARISING MATERIAL; LENSES (INCLUDING CONTACT LENSES), PRISMS, MIRRORS AND OTHER OPTICAL ELEMENTS, OF ANY MATERIAL, UNMOUNTED, OTHER THAN SUCH ELEMENTS OF GLASS NOT OPTICALLY WORKED - OTHER: OTHER, 70140090 under HS Code Others, and 68042100 under HS Code Others. were the top exported HS Codes by R Vietnam Technology Research Co Ltd in 2021.