Add 2 and Add 5 Barcode Specifications Retail barcodes (UPC and EAN) are strictly limited in the amount and format of the data that they encode. Add 2 or Add 5 barcodes give the vendors another two or five digits to identify the specific product, model, or issue. It is usually printed just to the right of the product code. For periodicals, an Add2 often indicates the issue, while other publications include a volume number.

Below is an Add 2 barcode example:

Below is an Add 5 barcode example: