Stone coral is put in an iron box, so the customs can't find it. According to the Law of People's Republic of China (PRC) on Exit and Entry Administration, people and articles entering and leaving the country are subject to customs inspection. However, coral stone is a non-prohibited import and export item and does not have the characteristics of posing a threat to public safety. The customs does not inspect it, which means that the stone coral is put in an iron box and has not been inspected by the customs, which means that it cannot be found. Some precious jewelry, watches, etc. are also non-prohibited import and export items, and can also be carried or mailed through security inspection. However, it should be noted that according to the relevant regulations, the customs has the right to inspect people and articles entering and leaving the country, and control administrative measures such as collection, detention, sealing up and dismantling within the prescribed scope.