Some sellers want to add more SKUs to their listings in WholeCell for their listings to gain more exposure and quantity in the channel. An example is if a seller has a T-Mobile (network) listing with, say, a quantity of 12, and they have five of the same product but with minor back scratches and three of another product with almost the same attributes but with an unlocked network. In WholeCell, you can add the unlocked network SKU and the one with the back scratches to the T-Mobile listing, so you have more quantities showing in the channel.

(On a side note, all these SKUs must first be uploaded to your WholeCell catalog.)

Add the secondary SKUs to the 'SKU connection' box on the listing's settings page in WholeCell like this.

After adding them, your stock levels will adjust as WholeCell adds the quantities of the other SKUs to the total count.

If you are using "shadow SKUs", you can also connect them to the main listing (or "parent SKU") this way.