iwc GROSSE INGENIEUR CHRONOGRAPH Mode D'emploi page 22

Using the chronograph
Start: To start the chronograph, press the start/stop button.
Flyback: You can start recording a new time immediately, even when the
chronograph is running. With the chronograph running, simply depress the
reset/flyback button fully as far as it will go. All three chronograph hands
are reset to zero, and a new measurement is started as soon as the button
is released.
Stop: To stop the running chronograph, press the start/stop button.
Reset: Depress the reset/flyback button fully as far as it will go. This will
reset all the chronograph hands to zero.
Aggregate time recording: You can add stop times together by pressing
the start/stop button again after the first measurement instead of the reset/
flyback button.
Water-resistance
The water-resistance of IWC watches is stated in bar and not in metres.
Metres, which are often used elsewhere in the watch industry to indicate
water-resistance, cannot be equated with dive depth because of the test
procedures that are frequently used. Water-resistance shown in metres
provides no indication as to actual use of the watch in the presence of
moisture and wetness, and in or under water. Recommendations for use in
connection with the water-resistance of your watch can be found on the
Internet at www.iwc.com/water-resistance. Your authorised IWC Official
Agent will also be pleased to provide you with information.