The fude nib was made of specail stainless steel ,You can write from 0.5 to 1.2 mm by varying the writing angle .
Instructions on How To Fill a Fountain Pen with Bottle Ink :
https://youtu.be/T8mfof7ZpU8
Instructions on How To Fill a Fountain Pen with Cartridge :
https://youtu.be/aDD-He8hRmM
Check more fantastic fountain pens in our store at :
www.amazon.com/shops/lanxivi