Final answer:
The highlighted feature is the combination of a stainless steel front with nylon temples, which brings a mix of durability and comfort to the Metal Collection eyewear.
Step-by-step explanation:
The primary feature highlighted in the description of the styles in the Metal Collection is B) The combination of stainless front and nylon temples. This feature emphasizes both the aesthetic and functional aspects of the glasses. The use of a flat stainless steel front is mentioned to signify durability and a premium feel, while the integration of nylon temples likely contributes to comfort and flexibility of the eyewear, offering a contrasting texture and potentially reducing weight. The flat design and the showcase of styles are secondary aspects within the context of this particular description.