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Usage and structure
Although ASINs used to be unique worldwide, global expansion has changed things so that ASINs are only guaranteed unique within a marketplace. The same product may be referred to by several ASINs though, and different national sites may use a different ASIN for the same product. In general, ASINs are likely to be different between the country sites unless they are for a class of product where the ASIN is based on an externally defined and internationally consistent identifier, such as ISBN for books.
Each product sold on Amazon.com is given a unique ASIN. For books with 10-digit International Standard Book Number (ISBN), the ASIN and the ISBN are the same. The Kindle edition of a book will not use its ISBN as the ASIN, although the electronic version of a book may have its own ISBN. In most cases, it is possible to convert an ASIN to obtain a corresponding EAN code.