When Omas reviewed its line of models after WWII, they definitely abandoned the old style roller clip and adopted a more modern design for their pens, which became piston fillers. The new line of models was named Extra and included facetted and cylindrical pens in three sizes as it had been for the Extra lever filler line of the 1930s.

The new Extras were identified with model numbers which were 555, 556, 557 from the smallest to the biggest and  used suffixes to qualify the design: S for the cylindrical models and F for the facetted ones.

The new line was simpler than its predecessors: caps were decorated with a single plain cap band and clips were straight, with the clip on the facetted models having what is known as a "diamond" design.

For the F line, Extra Lucens nibs were used, while  the S line  was fitted with Extra nibs.

The early facetted models were simply marked "Omas Extra" in cursive on the barrel. A bit later  a two-line engraving showing the patent number was adopted.

This Omas 557/F is in excellent condition with very minimal traces of use, if any. The pen is fitted with a superb F nib which performs extremely well in terms of flexibility, springiness and good flow of ink.