Esterbrook is most famous for it, but Wahl-Eversharp was the first that we know who made nib assemblies that screw in and out of its fountain pens. Click the headline on this Wahl-Eversharp Gold Seal to see the word "Flexible" written on the nib. This was just one of a series of nibs that could be screwed in or out to better suit the needs of its writer. We don't find this 14k gold nib to be super flexible. It seems more like a semi-flex these days. You will write a nice fine to roughly 1mm line. We restored this vintage pen with a new ink sac. Its woodgrain hard-rubber cap and barrel sport some wear and hazing. There is a little brassing on the lever, too. 12.1cm capped.