90308400 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, WITH A RECORDING DEVICE were the top imported HS Codes by R K BROTHERS in 2021.