Board Thread:Wiki Discussion/@comment-183.90.103.167-20130912073244/@comment-24026888-20131117174104

You're completely right actually. During the fusion process, fusion boost armors are considered mono-element two-stars, and act the same as any other 2-star.

So, technically, you could get anything from a rare up to legendary combining two fusion boost armors.

I'm not 100% on this, but I also think when mixing a fusion boost armor with a legendary, your options range anywhere from rare up to legendary. (Epics locked out, since 2-stars can't get those.)