Immediately after WWII Omas reviewed its lines of pens and replaced the old Lucens/Extra Lucens plunger filling mechanism with the more modern and easier to use piston.

The new piston was used for a line of pens which retained the old design with the roller clip and the slightly tapered ends. They were marked simply "Omas Extra" on the barrel and were marketed in three sizes: 555 ( lady), 556 ( standard/senior ), 557 ( oversize). Colors for this model were jet black, gray pearl, arco bronze and arco gray.

This Omas Extra is an Oversize in black celluloid fitted with a fantastic Omas Extra nib which is responsive, flexible and extremely performing.