Promo versions of games are issued in very small numbers directly by the publishers to retailers and reviewers slightly ahead of the official release of the game in the actual shops.
Saturn promos (sometimes known as â€˜Saturn silversâ€™) came on discs that had no artwork printed on them at all (hence the name) which can make them understandably hard to identify, so it is not uncommon for the original recipient to write the title of the game on the disc itself. However, they can still be identified by their matrix code (the code burned by laser on the inside ring) and if you hold them up to the light you can see the Sega logo and trademark on the outer edge. Saturn promos are much harder to come by than any Sony or Xbox promo games as their print run was much lower and it is quite unusual to find them in their original sleeve.
The copies this seller has come in original sleeves from Nelson Bostock Communications, who were working directly for Sega at the time to handle some of their Public Relations duties.
The seller also has XBOX, Playstation and Dreamcast promo games. Lots of cool items.