[Jedi]

Croc skin is considered leather. And I'm not sure what you mean by common. Were you expecting rubber? If so, there is one model in the Patek line up that comes with rubber straps.

But the basic contention here is that Pateks are generally dress watches, and in adherence to horological tradition, dress watches generally come with leather straps, and in some rare occassions, a bracelet is offered, Rolex notwithstanding. I happen to like tradition and Patek straps are very comfortable and well selected.

Sorry about the colour of the watch, I must have linked in the wrong image, but like I said, the homework is easily done.