This interesting pen betrays nothing about its origin or manufacturer. Undoubtedly old, from the turn of the twentieth Century, both slip-on cap and barrel are plain, without any ornamentation or decoration at all.  The cap is clipless. There are no imprints or other markings. The medium nib has definitely seen better days, showing signs of corrosion and wear. It is stamped " 14KT  GOLD PLATED". Although worn, it can still be used as a pen, although probably this is more likely to be of interest to a collector (who may recognise it).

It is an eyedropper filler - this pen has no rubber ink sac unlike later pens. To fill, the section (the part that holds the nib) is unscrewed revealing a cavity in the barrel. This is then filled using an eyedropper (not supplied)  - hence the pen's name.