4 positions potentiometer

Hey, I wanted to know what's the name of those switches, like potentiometers, but that have a fixed number of positions, let's say 4. Like the switches used in common fans, you know?
if possible, I'd like to know where to buy them aswell.
thanks

They are called "Rotary Switches" and they come in a wide variety of combinations of number of positions and poles.

A quick Google search on rotary switch will bring up a huge amount of information and potential suppliers.

They are called rheostats, they come in progressive regressive or step up & down.

I can see a lot of ignorance.