Alpina’s Extreme Diver watch pays homage to deep sea chronographs of yesteryear by presenting it in a black colorway. Made of anti-corrosive materials, it has non-scratch crystal and is outfitted with extendable wrist straps that can fit over a wetsuit. The bezel of the Alpina Extreme Diver is unidirectional, has luminous markers, and is used to set the maximum time a diver plans to be underwater. Therefore, it is vital that the setting cannot be accidentally pushed or knocked off. Having it move in only one direction means that time meant to be spent underwater can only be accidentally reduced, but not increased.