UPC-A encodes 12 numeric digits. The first digit identifies the numbering system being used with the following meaning:
0: regular UPC codes
1: reserved
2: random weight items marked at the store
3: National Drug Code and National Health Related Items code
4: no format restrictions, for in-store use on non-food items
5: for use on coupons
6: reserved
7: regular UPC codes
8: reserved
9: reserved
The next group of 5 digits identifies the manufacturer. This number is assigned by the Uniform Code Council (UCC). The next 5 digits identify the particular product and are assigned by the manufacturer. The last digit is a Modulo 10 checksum.