I was told that the NX props are actually Zoar props. I have also read on this forum that Zoar props are not that quiet. I have used Zoar props on my OS 1.60 and I like them also but I have to somehow quiet my gas engines with both muffler mods and correct prop choices. I think alot of the quiet props are thicker and have more rounded tips and I know the Zoars I have owned don't fit that description.