The Silent StepStick Protector is an add-on stepper module, designed to sit between the control board and stepper motor driver. It filters grain and vibrations from the 3D Printer with a parallel arm structure for quieter performance.
The board also features a flyback (free rotation) diode for stepper motor output, which prevents induced voltage while the driver is not in use. This prevents damage that can otherwise fry the drivers when the machine is powered off.
It is most effective at muting unwanted motor noise when used in combination with DRV8825 drivers and a relatively low resistance. The Silent StepStick Protect is however compatible with most models, including the A4988, TMC2100, TMC2130 and TMC2208 drivers.
(1) Silent StepStick Protector