Turn off the thermometer
Press and Hold the L/O Button
Continue to hold the start button when the F or C display appears. Watch for these displays to cycle over the display window.
Release the start button when the F display appears on the screen.
Listen for a beep and watch for the Braun ThermoScan ear thermometer to shut itself off, indicating that you changed the temperature scale to Fahrenheit successfully.
Follow the same procedure but release the start button when C shows on the display to switch from Fahrenheit to Celsius.