Free Trade Agreements have fields to include applicable blanket dates for products.
To utilize these fields, the shipment must be set for the appropriate export country and import country for the Free Trade Agreement Document.
The example below is for an export for the United States to import into Korea that are set on the Shipment Details screen.
The blanket date fields when then appear as options under the Customs screen.
This is what the FTA agreement will look like with the blanket dates populated.