Decouples the vibrations of the 3D printer from the desk it is standing on. The pool noodles I've used have a diameter of ~65mm and can be bought from Decathlon:
https://www.decathlon.de/p/schwimmnudel-schaumstoff-118-cm-rosa/_/R-p-330027
The length of the noodle parts are 65mm each.
To mount the feet to the printer, I've used the T-slot nut of @AHPrusai3MK3SKit:
https://www.printables.com/model/232808-t-slot-nut-for-prusa-mk4-and-i3-mk3s-and-prusa-min
The author marked this model as their own original creation.