Our XS pocket fountain pen is designed to allow changing the nibs. We offer additional nibs in various sizes (line thickness) and materials. All these nibs fit any XS pocket fountain pen and it is very easy to swap them. You just need to unscrew the entire nib system and screw in a different one.
Black Stainless Steel: EF, M, B
Polished Stainless Steel: EF, M, B, Calligraphy 1.1
Titanium: EF, M