ISO = International Standards Organization. It is a group of industrial quality specification people primarily in Europe but has made its way across the globe. If you do business on a serious scale in Europe it is almost insisted upon to become ISO certified. Almost but not quite like UL was in this country. As for the threads, I cannot help you but at least you know they meet some standard but don't think to highly of it. I certified many specifications and processes under ISO and it is no big deal. Sounds important but not really.
Ray Homiski
Elizabeth, NJ