If you wish to easily select your products for a campaign from the marketing platform on which you use your Cropink feed, data overriding may come in handy. You can either choose to override link or custom_label data (0-4).
Select your design from the "Designs" tab and scroll down to the Product Data Overrides section. From there you can click on the "+ Add Field" button and select the custom label of your choice.
Once you open the override window, you can either type in your desired name which will be assigned to a custom label, or use any of the existing variables, including those tied to a project: Design name (design_name), Design ID (design_id), Project ID (project_id).
Whenever ready, hit "Save". To update your feed right away, go to the "Settings" tab and click "Update Now".