To change the units to Fahrenheit:
1. Press Trigger to turn on the thermometer
2. Press & Hold SET button to go into settings mode (you will see and F-1 flash on the screen).
3. Press SET 2 more times until you see F-3.
4. In F3 module press ? or ? to change the units from C° to F°
5. Press SET again 2 times (after F4 the thermometer will shut off). Your options are now saved.