As is common with the Optima gold strings brand, the bass strings are gold-coated, more for the looks than anything else, as the coating wears off with time and use, which is no big deal. The sound is bombastic. The only downside is the strings' unusually large diameter, which also goes for the treble strings, causing binding issues at the nut. I think in the end you're better off with D'Addario's excellent EJ46FF.