According to the postal code database, 16300 16 in the postal code of Saertu District of Daqing City represents the province number of Daqing City, that is, the number of Heilongjiang Province; 30 represents the area code of Daqing City, that is, the area code of Sarthou; 0 1 represents the number of the specific delivery office in Saertu District, Daqing City, which is used to determine the specific delivery location of the mail.