SUUNTO Core - Manual (Page 12)

Button lock
You can activate and deactivate the button lock by keeping the lower right
[-Light] button pressed.
NOTE: You can change views and use the backlight when the button lock is
activated.
Changing values
To change a setting, you have to be in MENU . To enter MENU , keep the right
middle [Mode] button pressed down in the TIME , ALTI&BARO or COMPASS mode.
Any changes you make in MENU take effect immediately. For example, if you
enter TIME-DATE in MENU and change the time from 12:30 to 11:30 and exit.
The time will be set to 11:30.
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