If you use a converter because you like to use your own ink then I love my TWSBI Eco pens. Just stick it in the pot, twist the end and watch the ink fill the chamber in the pen beautifully. The “Eco” part is for ecological rather than economy (although I believe it is that too) 'cause you’re not wasting all that plastic in cartridges.
https://www.cultpens.com/c/q/brands/twsbi/twsbi-fountain-pens/twsbi-eco
