A very refined technique is applied such as a combination process of winding a metal rim around an acetate rim and connecting with the bridge, in addition a hole is made in the acetate to pass through the metal end-piece.
The lens shape is based on P3 shape, mixed with Crown-panto and pentagon, which is a very EYEVAN design.
Suit to the original 4 base lenses, the front curve and the cut of end-piece are completed with a sense of unity.