It is an application of screw-nut drive for removing a bush (in green) out of a hole (in yellow).Three blue springs tend to turn out three blue hooksRed slider can’t rotate due to grey cross pin sliding in slots made on transparent cylinder.

For removing the bush:

Hold the puller by one hand and place it on the bush.Turn cyan nut counterclockwise by other hand to move the slider down until the hooks hook onto the bush.Turn cyan nut clockwise to move the slider up (to pull the bush out of the hole).Once the bush is out of his hole, press radially the hooks with fingers, the bush will fall down.