The difference between the standard series and the metal series is in the supporting film, not in the lens itself.
The metal reinforced Blips lenses have ultra-thin and flexible metallic layers within the plastic supporting film; these layers allow an effective formability of the supporting film, making them more suitable for smartphones with camera positioned toward one corner of their case.
Demo video here
Moreover, the supporting films of the metal reinforced series have brigther colors, thanks to the reflectivity of the metallic layer.