Last sunday I found in a flea market a german scholastic pens, I always take them because they usually write very well and I like piston fillers, this pen made by Compaktor has something of unusual, indeed it is not a piston filler but a vacuum filler, operated by pressing the transparent button at the end of the barrel:
This really got my interest since up to now I was not aware of this type of german pens.
Alfredo