iwc 3717 Mode D'emploi page 20

Technical refinements of the Pilot's Watch/Spitfire
Chrono-Automatic
Your IWC watch shows you the time in hours, minutes and
seconds as well as the day and date. With the integrated
chronograph, you can measure any length of time up to
12 hours in seconds, minutes and hours. The mechanical
movement with automatic winding has 25 jewel bearings
(synthetic rubies) and has a power reserve of at least
44 hours when fully wound. The watch case is water-
resistant up to 60 metres (according to standard
ISO 2281) and is protected by a sapphire glass of hard-
ness grade 9, which is secured against displacement from
a drop in air pressure at extreme altitudes. The water-
resistance rating of a watch in metres is a theoretical
value, which must not be confused with the depth of a
dive. Your IWC watch has a double case; the soft iron
inner case assures optimal protection against magnetic
fields. To ensure that this extraordinary watch continues
to perform its tasks in future, it is essential to follow a
few important operating instructions.