As I progress with my X-Metal collection I've become intrigued by the many color combos I see. They all seem to be referred to as TiO2. I was under the impression that TiO2 meant x-metal stems and nose bridge with plasma orbitals. Then I see the gold combos, black combos, polished rather than plasma, etc. Is the TiO2 term just used in a general sense to cover any combo? What was original oakley release TiO2? And just what the hell does TiO2 mean or stand for anyway?