What do you use to raise height of your chairs?

You'd think something would be offered to bolt in between the pedestal and the seat itself, something similar to what is used in lower-end cars, a lever to ratchet the seat up and down....nothing electric, all mechanical.

I wonder if you could take one from a junk car and retro-fit it somehow. But it would add height. You would likely need to cut down the pedestal and weld it again. It would make for an interesting project.