Leupold GX-5i Operating Instructions Manual page 27

5) To save the changes and return to ranging mode, let the unit sit idle
for a least 30 seconds until an automatic power-down occurs, or
simply press and hold MODE for at least 2 seconds.
NOTE:
If yards is selected, the temperature will automatically be measured by
Fahrenheit. If meters is selected, the temperature will be measured
in Celsius.
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