I'm not sure if that's the one I have (can't find a model number,) but on my Inkbird, if you press and hold the set button until it gives you a flashing display to adjust with the arrows, then keep repeatedly pressing the set button, it will cycle through all the parameters you can set, like temperature, differentials, alarms, and, eventually, Fahrenheit or Celsius. When you're finished, press and hold the set button until it goes back to normal operating mode and the settings are saved. Or when all else fails, read the directions.