Here is a set of 2 (two) collectible OMAS Rebecca Moss pens:

One Fountain Pen in royal blue celluloid and silver plate with 14k White Gold Medium Nib. 
   - Limited edition: Inscribed with 5/100 on pen (This exact fountain pen, by itself, but number 7/100, was sold on Sotheby's for $1400, for reference.   https://www.sothebys.com/en/buy/_omas-rebecca-moss-blue-celluloid-fountain-pen-47b0.  ) 


One rollerball / ballpoint "Rolling Arte Italiana" pen in royal blue celluloid and silver plate.

I believe these were purchased new circa 2000.

In overall gently pre-owned, excellent, shiny condition. Some minor scratching on clips, that should show in the photos. (My father is the original buyer of these - one owner.) 
There is some ink at the base of the fountain pen, as well as some small amount of residue on the cap - but it appears that this would come off with buffing or professional cleaning. (I don't want to take the pen apart or do anything to clean it myself.)

Zoom in on photos for more info and ask for more if you need them. 

"In the early 2000s Omas did a number of special limited editions for the Rebecca Moss store in New York City using some of the rarer celluloids. The catalogue featured five Limited Edition (100 units) OMAS Bologna and namely: Saft Green, Royal Blue, Pearl Grey, Scarlet Red and the Arco Brown with the Spina di Pesce configuration. 
Back then Saft Green, Royal Blue, Pearl Grey, Scarlet Red and the regular Arco Brown were already part of the OMAS Paragon Catalogue." See end of this listing for more info on these pens.