The upc-supplemental-2 bar code type represents a 2-digit decimal number that can be used in conjunction with the upc-a bar code type.

Typically the code is placed to the right of the upc-a bar code. The gap between the rightmost bar of the upc-a code and the leftmost bar of the supplemental code should not be less than 2.31mm and should not exceed 3.3mm.

The nominal size is 0.26in x 1.02in (w x h). The bar code is painted without padding at the sides.