Fortis Watch Aviatis Aeromaster Stealth Chronograph 656.18.18 LP. Just like its little day/date brother, the 655.18.18 Aeromaster Stealth, the Fortis 656.18.18 Aeromaster Stealth Chronograph comes in a black PVD powder coated stainless steel housing, thereby staying true to the name Stealth. The black also continues on the face, establishing the base for a perfect pilots timepiece. The most striking signs of perfection are the orange Compteur and second hands. The large date display as well as the large numerals are further trademarks of the Aeromaster series.