I clearly dislike modern converters, especially the one depicted,
formerly belonging to a cute little Pilot Birdie.
You operate it by pressing the U-bar, one prong of which is fixed
inside the metal collar, the other prong is movable and flattens
the ink sac.
Unfortunately, the end of that movable prong is somewhat sharp
and eats into the ink sac in no time at all. Result: the ink sac
Claes in Lund, Sweden