From the manufacturer:
This series features a traditional broad edge nib with a great degree of flexibility. Our most popular of the three broad edge offerings, the C-Series nib is meant to be held at a constant angle throughout the creation of any traditional calligraphic alphabet (with minor variations needed, depending upon the lettering style). This consistent angle gives the lettering artist the desired thick and thin strokes usually associated with broad edge calligraphy, such as Roman, Carolingian, Uncial, Italic, Gothicized Italic, Blackletter or Neuland.
Available in (6) nib widths in the original C-Series design, or (5) nib widths in our left-handed C-Series variation and suitable for use with any straight/classic style penholder.