The first digit of a UPC-A is the manufacturer’s identification number. It is called the number system character. The following table shows you what different number system characters mean
0: Standard UPC number
2: Random weight items (fruits, meat, vegetables, etc.
4: In store marketing for retailers (a store can set up unique barcodes for themselves, but no other store will be able to read them)
6, 7 Standard UPC number