I have the very first Nikon F-S adapter that Amedeo Muscelli produced. He made it after I was unable to find one of the Cosina versions, and contacted him about making some for those of us Nikon rangefinder users who might want one. He agreed and made a prototype, and incredibly, insisted on shipping it to me for my approval before accepting payment.
It works very well, but because I have Cosina 25 and 21mm rangefinder lenses, I use it with my Vivitar 19 and 17mm Nikon-mount SLR lenses instead and have gotten very nice results with it.
Well worth the money if you want some extra versatility from your Nikon rangefinders.
Robert