They come with a specific key from the manufacturer as in the picture below.
As you might expect, those keys are sometimes lost or misplaced.
I have seen places where people forget and leave them on the faucets only to find them gone.
As I described in my earlier text, the 4-Way Key is a universal tool that fits a variety of different faucets.
It's always wise to have a backup or two.
“It’s always wise to have a backup or two.”
Or a hundred! Those keys would end up with Beau’s dozens of cans of nuts, bolts, screws, washers and nails-yet-to-be-straightened, LOL!
I’d keep one for myself; I ALWAYS know where MY stuff is. :)