You can use custom labels to:
- list specific features in your Shopping ads
- subdivide a product by specific features that you decide
- have Google subdivide your product into specific relevant categories
- target different countries within the same Shopping campaign
Explanation:
With Shopping campaigns, you can use custom labels when you want to subdivide the products in your campaign using values of your choosing. You can use custom labels to indicate that products are seasonal, on clearance, best sellers, etc
Read more here: https://support.google.com/adwords/answer/6275295
