The 55X series of piston fillers was introduced by Omas in the late 1940s.

It comprised cylindrical and facetted models in three sizes: 555, 556 and 557. Facetted models were identified with the letter "F" following the model number while cylindrical pens had the "S" suffix ( "F" means Facetted, while "S" means semplice, simple in English)

This line of pens was extremely successful and remained in production till the 1960's. All the models were highly reliable everyday users and had very beautiful 14 ct nibs.

The facetted line was fitted with Omas Extra Lucens nibs, exactly like the ones Omas had used in the 1930's for the top line of the Extra lucens pens, while  cylindrical pens had Omas Extra nibs.

The first Omas  557/F pens to be marketed had a simple "Omas Extra" imprint on the barrel. In the following years, the imprint on the facetted models was updated witht he addition of patent numbers.

This Omas 556/F in gray pearl celluloid is in  very good condition with only a slight greenish shade of the celluloid.  The cap lip has been unfortunately slightly shortened but it doesn't affect the closing of the pen at all.  

The nib is pretty generous, very smooth and flexible.

The pen is priced on the basis of condition.