The Explorer I was designed as an expedition watch to conquer Mt Everest. This is a robust watch resistant to harsh weather conditions such as extreme heat, cold, shock, and moisture. Even though a luxurious watch, it has a rugged but elegant look. If you are into the expedition and want a reliable yet discrete timepiece, then you should consider having an Explorer I. It has a self-winding movement and a certified chronometer. The case is 36 mm.