Here are two variants of damping mount for the PixHawk 6c mini flight controller. It filters out vibrational noises for the IMU.

The wider version has a larger area (could mean more stable) but if your frame is space constraint please use the narrow version.

The 3.2mm sunken face is for Velcro tapes to allow quick installation and removal. If you are using thinner double sided tapes please just use the higher surfaces around it.

It fits the common damping ball you can purchase anywhere. Here is an example linked. I've also included the damping ball's model for your sizing reference.