Have a look into the technical aspect of a Double Split, for instance:
it is a mechanical chrono where you can store a once taken time (best time of a race) and than set the "other" chrono back (as it is a
double chono) and start again.
And if the new time is better you can even make an adjustment of the former best time and store the new best time by only pushing a
pusher twice and there you are: the former best time has been beaten and with the same hands you have stored it.
There is no other watch on the market with this "complication".
One thing is a bit of a minus of the DS: it is rather big, BUT for a reason
.
Moritz