Keyboard Monitor Mouse What Are Those Things Called That Let You Use 1 Monitor Keyboard & Mouse For 2 Computers?

What are those things called that let you use 1 monitor keyboard & mouse for 2 computers? - keyboard monitor mouse

I have 2 computers and want the same monitor, keyboard and mouse to use for both. I've seen it already, but I do not know their names. It's like a splitter that is connected to 1 monitor keyboard and mouse for 2 computers and allows you to edit your diplay between the 2nd