Your listings are required to have a SKU in the Custom Label in order to import your products from eBay. Please note that you will need Selling Manager or Selling Manager Pro to access the Custom Label field. Currently, there is a limit of 100 items for total quantity of items when using Selling Manager or Selling Manager Pro.
Add a SKU to the Custom Label for a listing on eBay:
1. Go to My eBay > Selling Manager > Active Listings. If you don't see the Custom Label column, click "Customize" to add it
2. Check the "Custom label" box and then click "Apply"
3. In the Custom Label column, click "[Add]" to enter your SKU value
4. Once you've added a SKU as a custom label, your listing will import the next time you download listings from eBay.