Fahrenheit oral thermometer?

Years ago I found one at Corral Centro. Recently found another at a med store but though it says “Measurement in F or C” on front of the box, I was unable to switch to F. Neither the store owner nor the cashier could either. They said they would order a video with instructions. So far, the video hasn’t shown up.

Now I wonder if the wording on the box actually means one or the other, not both. Does anyone know where I can find a F. oral thermometer?

Jon: .

City: Cuenca