Davosa Watch Ternos Professional Nebulous Automatic Smoke Black 16153550. Swiss watch manufacturer DAVOSA, renowned for its functional divers’ watches, is reinterpreting a classic from its diving collection: a special model of the Ternos Professional is launching with the designation ‘Nebulous’. The Ternos Professional series is specially designed to meet the exigent needs of extreme divers. It displays a very high water resistance of 50 ATM, it is particularly robustly built, and it has an automatic helium valve set at 9 o’clock, which is essential when using a pressure chamber in very deep water.