SUUNTO M5 - Manual (Page 14)

6 USING BACKLIGHT AND BUTTON LOCK
Press to activate the backlight.
Keep pressed to lock or unlock the button. When the button is
locked, is shown on the display.
TIP: Lock the button to avoid accidentally starting or stopping your
stopwatch.
NOTE: When the button is locked during the exercise, you can still change
the views by pressing .
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