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.
Can be used with a Speedball Oblique Penholder (RM18), Adjusted Oblique Plastic Holder with Metal Flange (RM35) or the Brause Straight Holder (RM14).