Per Wikipedia: The luopan or geomantic compass is a Chinese magnetic compass, also known as a Feng Shui compass. It is used by a Feng Shui practitioner to determine the precise direction of a structure or other item. Since the invention of the compass for use in Feng Shui, traditional feng shui has required its use.
I don’t know a lot about Chinese culture, but I recognized it instantly from its appearance in Session 21 of Cowboy Bebop: “Boogie Woogie Feng Shui“.
They also had what looks like a souped up version at the same sale:
