Yes, this has always mystified me. For "masculine-oriented" models I think that "red gold" sounds more appealing than "pink gold" and I have always used "red gold" when mentioning the metal in English as it is the direct translation of what Lange says in German publications (implying 25% copper, see my previous post). That said, I continue to wonder what is actually the composition of the metal that Lange uses since they translate rotgold into "pink gold" which technically is 20% copper (with 5% silver) as I mentioned.