IWC Schaffhausen Aquatimer Split Minute Chronograph Mode D'emploi page 26

Operating the chronograph
Start: Start the chronograph by pressing the start-stop button.
Stop: Stop the chronograph by pressing the start-stop button again.
Resetting: Press the reset button. This will cause all the chronograph hands
to fly back to the zero position.
Aggregate time recording: You can add the stop times together by press-
ing the start-stop button again, instead of the reset button, after taking the
first measurement.
Seconds counter: The graduation for the central seconds stop hand is
situated at the edge of the dial.
Minutes counter: The 30-minute graduation with a slow jumping hand is
situated at 12.00 on the measurement indicator. This hand makes two
complete revolutions in one hour.
Hours counter: The 12-hour graduation with short lines for the
indication with a continuous hand is situated at 6.00 on the measurement
indicator.
Split Minute function – On (I)
Setting the rocker switch to position (I) engages the Split
Minute function and causes the Split Minute hand to
stop, while the minute hand continues to run. You can
read the duration since activation as the difference
between the two hands. Setting the rocker switch to
position (0) causes the Split Minute hand to fly back
to a position below the minute hand. The watch is now
once again ready for minute measurement.
1 ⁄ -hour
2