iwc IW3931 Operating Instructions Manual page 7

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THE TECHNICAL
REFINEMENTS OF THE
DA VINCI TOURBILLON
RÉTROGRADE
CHRONOGRAPH
Your IWC watch shows you the time
in hours and minutes and the retro­
grade date. You can use the integrated
flyback chronograph to measure any
period of time in seconds, minutes
and hours. Stop times can be added
together. The mechanical movement
with automatic winding has a power
reserve of approximately 68 hours
when fully wound. Your Da Vinci
Tourbillon Rétrograde Chronograph is
protected by an arched­edge sapphire
glass of hardness grade 9 on Mohs'
D A V I N C I T O U R B I L L O N R É T R O G R A D E C H R O N O G R A P H