Amazon's FBA prep requirements are strict, specific, and unforgiving. Send inventory to an Amazon fulfillment center without proper prep and it gets rejected, returned, or destroyed — at your expense. Here is exactly what Amazon requires and why.**FNSKU Labeling**Every unit sent to FBA must have an FNSKU barcode applied. FNSKU stands for Fulfillment Network Stock Keeping Unit — it is Amazon's own barcode that identifies your specific listing, separate from the manufacturer barcode.Why it matters: without an FNSKU, Amazon cannot track your inventory separately from other sellers of the same product. Your units could be commingled with other sellers' stock — a major quality control risk.The FNSKU label must cover the manufacturer barcode completely. It cannot be crooked, damaged, or peeling.**Poly-Bagging Requirements**Amazon requires poly-bagging for: clothing, fabric items, plush toys, loose products that could separate, and items susceptible to moisture or dust.All poly-bags 5 inches x 5 inches or larger require a suffocation warning on the bag. This warning must be in a readable font size based on the bag dimensions — Amazon specifies the exact size.**Bubble Wrap and Fragile Items**Fragile products — glass, ceramics, electronics — must be bubble-wrapped with enough coverage to pass a drop test. Amazon specifies that fragile items must be packaged to withstand drops from a height of at least 3 feet.**Box-Level Content Labels**Every carton in your FBA shipment must have a box-level content label showing the box number (e.g., 1 of 5), the shipment ID, and the contents. Amazon uses these to reconcile received inventory against your shipment plan.**Common Prep Mistakes That Cause FC Rejections**The most common causes of FBA receiving rejections: FNSKU label applied over wrong barcode, poly-bag missing suffocation warning, incorrect box-level content label, and pallet exceeding height limits.3PLCity handles all of these correctly, every time.