This is a popular Copperplate nib, designed for fine writing.
Large, durable nib appropriate for writing at x-heights of 3/16" to 1/8". Thicker hairlines than the Hiro #40, but is exceptionally smooth-gliding. Moderately thick swells.
The nib will have an invisible protective serum on it to keep it from rusting. Please remove this before use, by dipping the nib in soapy warm water and rubbing off the film.