Hi everyone, II recently bought a lot containing a couple of Parker 15 fountain pens and discovered that some of them have numbers on their nibs rather than the usual X/F/M/B. I attach the photos of four nibs I have below: Does anyone has any reference regarding these nib codes? Could not find it anywhere. Thank you in advance. Filip PS. "2" is really nice - it is so fantastically smooth that I will probably keep it for myself.