Why are they all looking at their watch while they are getting ready for the Destination Baselworld 2013? You will have the answer in a few days...
Hautlence Destination 01
It is perpetual because it automatically takes into account months with 30 days and the 28 or 29 days in February. It therefore incorporates a mechanical memory whose sequences are repeated every 48 months to correspond to the cycle of leap years.