In philately, stamp hinges, or mounts, folded, transparent, rectangular pieces of special paper coated with a special gum. Used by stamp collectors to attach postage stamps onto the pages of a stamp album. Stamp hinges were created way before stamp mounts, therefore they’re more used by collectors, even though nowadays collectors prefer stamp mounts.
The shortest end of the stamp hinges is moistened and affixed to the stamp, the longest end is likewise affixed to the stamp album’s page. The stamp hinges was created to keep the stamp affixed to the page while still allowing it to be lifted to examine its back, for instance to see the watermark or expert marks.