It is always ready for action, ticks automatically, and knows the date. Ahoi date Atlantic is waterproof up to 200 meters and is equally appropriate for recreation in the mountains, in the city, by the sea. A robust steel case, with a sapphire crystal back with six screws and the crown guard, prevent water and dust from entering the movement. The NOMOS DUW 5101 automatic caliber was made in Glashutte tradition and is equipped with the NOMOS swing system, the now-famous escapement that demonstrates the caliber that achieves the very best accuracy.