90158090000 under HS Code SURVEYING (INCLUDING PHOTOGRAMMETRICAL SURVEYING), HYDROGRAPHIC, OCEANOGRAPHIC, HYDROLOGICAL, METEOROLOGICAL OR GEOPHYSICAL INSTRUMENTS AND APPLIANCES, EXCLUDING COMPASSES; RANGEFINDERS - OTHER INSTRUMENTS AND APPLIANCES: OTHER, 85442049000 under HS Code Others, and 85291099000 under HS Code PARTS SUITABLE FOR USE SOLELY OR PRINCIPALLY WITH THE APPARATUS OF HEADINGS 8525 TO 8528 -AERIALS AND AERIAL REFLECTORS OF ALL KINDS; PARTS SUITABLE FOR USE THEREWITH: OTHER: OTHER were the top imported HS Codes by PHILIPPINES INSTITUTE OF VOLCANOLOGY in 2021.