You will need to install a user script manager extension to install this script.
This script adds links from Amazon product pages to the same page (if available) on other Amazon sites around the world.
The links can be accessed from any product page, but many products are either not available in other markets, or are not available under the same Amazon identifier. Books, CDs and DVDs/Blu-ray discs tend to produce the best results.
By default, links to the US and UK sites are added, but links to any of the following international Amazon sites can be configured:
To modify the displayed sites, navigate to a product page and open the preferences dialog by running the Configure Amazon International Links userscript command.