These things really do work! They dampen the vibration from the stepper motors, making them quieter. Can be used primarily on X and Y steppers since they do the most work.
NOTE: Price is for 1 damper
For the X Axis, you will need 2, M3x6mm screws.
If your pulleys are pressed on such as with the Ender 3 PRO, this will not work without re