What’s the EPC header for?

The EPC header is used to indicate the format of the EPC code, (i.e. the length of field partitions), and was designed to make the system flexible. For instance, the header tells the reader whether the tag has a 64-bit or a 96-bit EPC. The header also makes it possible to divide the data partitions in different ways, so a manufacturer that makes large amounts of only a few products could shift digits from the object class partition to the serial number partition.