Flat Rate for Specific Item

I searched but, did not quite see the magic thread.

How can I specify that a particular product will have a specific shipping charge plus the other items in the cart?

So Item "A" needs a shipping charge regardless of its weight entered.

I sell a few items that are going to cost $25.00 to Ship UPS anywhere in the US 48. They charge for the volume not the weight. 48" box.

I have a zone well defined for the US 48. Is this a table weight?

The trick is mixed carts which, when they order small items as well as the behemoth box then of course I will not charge extra.