This hanky is a promotional item for steel water heaters in Rorschach, Switzerland. Evidently the brand name is Imperator but don't hold me to that. The hanky is printed with a gray-toned photo of Rorschach. This looks like the kind of photo Anya Hindmarch used for BA handouts.
The picture is printed on a nice quality cotton hanky. It is unused and 11 inches square.