This pen require a syringe rubber plunger head to work, 2.5ml syringe.
The piston mechanism must be printed in place, with a 0.2 nozzle. I never tried the 0.4 nozzle.
The pen must be sanded, especially the inside of the body.
The pen is made for a JOWO #6 nib.
Edit. I don't know why but the pics are not showing.
Filoalfa grafylon, formfutura ASA, unbranded PETG, Cheap chinese PLA PETG, ASA, PLA