Amazon employs a barcode-driven system. Every product you send to a fulfillment center requires a barcode so that it can be tracked throughout the fulfillment process. You have three options for labeling products sent to a fulfillment center: You can use existing UPC or EAN barcodes for eligible products; you can use an Amazon-generated barcode, known as an FNSKU, that you affix to the product yourself; or you can use the FBA Label Service to apply barcodes to your products for a per-item fee.