Duettes that aren't Coro?

In browsing the book American Jewelry Manufacturers by Dorothy Rainwater, I found reference to a company called "Certified Metals Company". In the description it shows a logo that says "Loves Duette" for wedding rings and engagement rings, and mentions an ad from 1978

Given that this brand was used for fine jewelry, and apparently generally for rings, it will probably not cause any confusion in identifying pieces that we may find, but just in case, I thought it might be good to know that the name was actually used for items other than Coro.