Amazon requires it. They’ll also charge you $0.20 a unit for it… Let us save you some money!
Each Unit you send to Amazon for fulfillment needs a unique scannable bar code to enable storage at a fulfillment center. If you have barcode on a unit that is not unique (for example, if you have the same barcode for an product that comes in many colors or sizes) you would need to apply a unique FNSKU label printed from your Seller Central account.
Other types of labeling:
‘This is a Set. Do Not Separate’ Labeling ($0.20)
Suffocation Labeling ($0.20)