Suunto D4I User Manual page 37

To modify gas mix settings:
1. While in Nitrox mode, keep [DOWN] pressed.
2. Press [SELECT] to enter the Nitrox setting.
3. Scroll to Mix1, Mix2 or Mix3 as desired and press [SELECT].
4. Define the selected mix as Primary, Secondary or Off with [UP]
or [DOWN] and confirm with [SELECT].
53. 6
Mix1
Primary
5. Adjust the blinking O 2 value with [DOWN] or [UP] to match the
oxygen % of your tank and accept with [SELECT].
6. Adjust the blinking PO 2 (oxygen partial pressure) value with
[DOWN] or [Up] and confirm with [SELECT].
7. Adjust other mix settings as needed.
8. Press [MODE] to exit.
NOTE: If the oxygen content of a mix is set to 22% or above,
the setting value remains until changed. It does not automatically
revert back to 21%.
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