"Amazon Standard Identification Numbers (ASINs) are unique blocks of 10 letters and/or numbers that identify items. (...) For books, the ASIN is the same as the ISBN number, but for all other products a new ASIN is created when the item is uploaded to our [Amazon] catalogue.
You will find an item's ASIN on the product detail page alongside further details relating to the item (...)."
ASIN on Product Detailpage 1 - URL
ASIN on Product Detailpage 2 - Product Information