This pen is an ink eraser pen. You cannot write with it like any ordinary pen.
It erases royal blue washable ink by Pelikan, Lamy, Montblanc, Parker etc. and
ist doesn't work with Noodler's inks. You erase your mistake and then you use a
blue fineliner to overwrite it. German students love this kind of pen because at
school and for homework it is very helpful.