1930 - This pen is a good example of an early Symetric. Conklin was in such a hurry to make a streamlined pen that they basically rounded the ends of existing pens. Look at this pen compared to a standard straight Endura. It is just rounded off. The pen retains the annular lines from the earlier lines and adds the crescent above the clip.

1931 - This is a good example of a typical Symetric. Black is not the most popular of colors. They are eligant and are generally harder to find than there more colorful counter parts.