Good explanation on the difference between US and Import when you are looking to save a few bucks on equipment. If you have a lot of $$ invested and are not aware of this difference, please read the entire (worthwhile) article at the site.
The Camera Gray Market Explained
Much of the photographic gear sold in the United States is imported merchandise from other countries. These products have authorized distributors in the United States who have been authorized by the manufacturer to import and sell their products to dealers.
Gray market items (also referred to as parallel import) are products that are not brought into the country by the authorized distributor. These products, which are often purchased in countries where the exchange rate is particularly favorable, are purchased and resold in the United States by other parties. It’s not an illegal practice.