Products with the main label will be displayed to all logged in and non-logged in customers regardless of their assigned segments. Products with this label are the default set of products for all customers. It is not possible to hide some of this set of products for a specific segment.

To set the main label you should:

1. Log in to Administration Panel
2. Go to  "Configuration" card
3. Choose "Product visibility" tab
4. In the upper field, select the main label from the drop-down list 
5. Click on the "Save" button to accept the changes