The container seal is marked with a date to identify the goods, and sometimes seal numbers are printed on the corresponding bill of lading. In addition, the seal can be used to judge whether the goods in transit was open, which means "seal" in good condition or not is one of the absolute bases for the carrier and the consignee to deliver the goods, which reflects that the seals as the credentials for the shipper, carrier and consignee to deliver the whole box of goods is very clear and important . 

Simply speaking, its role is: 

1.It is used to ensure that the goods are not opened during transit. The main point is whether the seal is intact. 

2.Seals are marked with a label to identify the goods, which will be reflected in the bill of lading. The purpose of checking the seal is to determine if it has been opened in transit. If it is opened, the label on the new seal will change, which will prove that the box has been opened. Then it will be examined. It is also to ensure that the goods are properly delivered to the collector.