A beautiful extra fine fountain pen nib with flex! Made exclusively for our fountain pens, all of my nibs are tipped with incredibly hard-wearing iridium for super smooth writing, and are plated in a 14k gold or Stainless Steel for a classically stunning look. As a bonus all nibs can be interchanged so you can easily write in different styles whenever it suits you. Extra Fine Semi-Flex - A beautiful extra fine fountain pen nib with flex! This is a great middle-ground between the Pro Flex and our classic fountain pen nib, with its smooth writing experience and minimal maintenance. By applying a little pressure the nib will flex from 0.5mm to 1.5mm.