FNSKU (Fulfilment Network Stock Keeping Unit) barcodes are Amazon barcodes used to identify and connect products with its sellers. FNSKUs are only for Amazon FBA sellers. Once you set up the product(s) you plan to sell with FBA, Amazon will assign you with a FNSKU code. Once you have your FNSKU barcode, you can print them and add them to your products.
FNSKU barcodes can be printed with MarkMagic.