You may want to e-mail niles (username nilsatcraft)he works for CSU. I think the calligraphy nib in their catalog only fits pens that have the same size writeing nib (there term for the part). I believe Anthony (Penworks) mentioned in an other post that they carry replacement nibs for the larger pens like the gentleman or ligero but they are not in the online catalog. Not suer if this is true or if they have a calligraphy nib for them Niles would know for sure.