FNSKU – Fulfillment Network Stock Keeping Unit
A barcode assigned by Amazon that is unique to each product. FNSKU is a way that Amazon connects sellers to their products once they arrive at a fulfillment center.
Amazon provides FNSKU labels that can be printed and used to cover existing barcodes on a box. Alternatively, a factory can print the FNSKU directly on the box or Amazon can label the boxes themselves once they arrive at the fulfillment center for a fee. You can use the product’s UPC but you risk “commingled” inventory where other sellers’ inventory is mixed with yours.