I have been eyeing the Hamilton Khaki Aviation X-Wind Auto Chrono ever since it first debut back in 2016. Granted the special complication that the watch was designed for would not be useful to me, I was taken more by the beauty of the design than anything else.
The number of pushers and crowns on the watch intrigues me. Having two inner bezels as well as an external bezel in a watch appears to be an overkill. Nevertheless, the watch has a few ingenious use of the moving parts of the watch to do rather complex computations. In reality, the Hamilton Khaki Aviation X-Wind Auto Chrono (the X-Wind for short) is a mechanical computational device that is already obsolete when computers are already taking over the same job and more.
Looking passed the question of efficiency, you start to appreciate the way form and function designed into the watch would be able to do such calculations. To me, what makes this watch desirable is the way a mechanical 'calculator' has been made to look like a brilliant piece of art. The X-Wind should be in the collection.