In the 1980's Omas restyled its lines of pens.

Top of the line was the big Paragon flanked by the 557 Ogiva.

The imprint on the barrel of Ogivas were originally OMAS 557/S (matching the imprint on Paragons whcih was 557/F) and later on it became simply Omas Extra. Both early Paragons and Ogivas had a serial number imprinted on the barrel, which was later on abandoned. Paragons, and Ogivas were fitted with two tone nibs.

In the late 1980's a simplified version of the 557 Ogiva was introduced with a single cap band and without the band on the section. 

For more details about the evolution of these models, you can check the blog:

https://www.tenpen.it/article/milord-paragon

This Ogiva  is part of the 1990s production an has the Omas Extra engraving on the barrel; it is fitted with a very smooth semiflexible nib.

The pen is pre-owned but in pristine condition