Liliput

It was way back in 1910 when the German company Kaweco produced the Liliput model!
The fountain pen is completely made of solid aluminum with a steel nib.
Only 9.7 cm long when closed, making it one of the smallest fountain pens ever produced to use standard cartridges.
To make writing easier, the screw-on cap on the barrel makes the pen 12.5 cm long.