Why do brands include more than one tourbillon to a watch movement? The primary answer to that question is because it makes the watch more accurate. Originally developed to limit/eliminate the influence of gravity, the tourbillon is still the most efficient in a pocket watch, because that remains mostly in the same position. Their effectiveness in wrist watches is limited, but two (or more) is always better, as a differential can take the average rate of the tourbillons and combine them into a single output, which will, by the law of averages be more precise. These are some of our favorite watches with double tourbillons!