Sellers often have multiple Shopify variants mapped to a single Flexport SKU (DSKU), Flexport can place Shopify Fast Delivery badges on all variants for a DSKU.
Bundling Apps
Some Shopify Bundling apps create multiple variants, each of which represent different quantities of the same item. Such apps will result in DSKUs that are mapped to multiple Shopify variants, and Flexport will be able to place the Free 2-Day Delivery badge on all of the variants.