Copy-thin-book is a free Chrome add-on developed by sixthday. It falls under the category of Browsers and is specifically classified as an Add-ons & Tools subcategory. This handy tool allows users to easily copy the information of a Doujinshi from popular online Doujinshi shops such as とらのあな (Toranoana) and メロンブックス (Melonbooks).

With Copy-thin-book, users can effortlessly extract the title, circle name, author name, post-tax price, category, and URL of Doujinshi products. The extracted information is conveniently copied to the clipboard, making it easy to use in other applications or for personal reference. It should be noted that this add-on currently only supports Doujinshi information and does not include information for Doujin CDs, merchandise, or games.