Ohto Tasche Aluminium Fountain Pen
OHTO Tasche is a super-compact fountain pen, measuring just 98mm when closed, but open is a full-size pen at 145mm long.
The secret is the extra-long cap, which almost entirely swallows the rest of the pen when closed, but posts firmly onto the top of the pen to create the full length.
Takes the short international standard cartridges only, we haven't found a converter yet that fits...
Lighter than the Kaweco and the nib is comparable to a Fine Kaweco in our opinion.