90318090 under HS Code Others, 90308990 under HS Code OSCILLOSCOPES, SPECTRUM ANALYSERS AND OTHER INSTRUMENTS AND APPARATUS FOR MEASURING OR CHECKING ELECTRICAL QUANTITIES, EXCLUDING METERS OF HEADING 9028; INSTRUMENTS AND APPARATUS FOR MEASURING OR DETECTING ALPHA, BETA, GAMMA, X-RAY, COSMIC OR OTHER IONISING RADIATIONS- OTHER INSTRUMENTS AND APPARATUS: - OTHER: OTHER, and 90249010 under HS Code Others were the top imported HS Codes by A CHAU EQUIPMENT AND ENVIRONMENTAL TECHNOLOGY JOINT STOCK COMPANY in 2021.