Supplementary Product Selection - Customer can select supplementary products on the checkout page.
This could be used for adding any free products to the order. The product pricing would therefore be set at zero. Or it could be a extra wrapping service, or special treatment of order. Products added to this list will be displayed on the basket page only as in the example below. They are meant as a supplementary addition to an order - not products in their own right which would be selected via the normal means.
How the setup screen is displayed in the administration area. Note how the title is displayed to the customer on the basket page.
Example on how the customer will see this option on their basket page. If a selection is made this will appear on the checkout page and the order total will be updated accordingly. If products selected they will be visible on all order view pages.
Only one instance of this type of field is allowed.