Moon Gel ! This is the best vibration absorption material.
The self-adhesive gel sticks to the surface of drums, cymbals, and most percussion instruments.
Wait why is it sold here if it's used on percussion instruments?
Because it's really good when used under the APM (or any flight controller). It will absorb the vibration and make your flight controller happier!
The Moongel Damper Pad is made from a soft non-toxic gel, and is packaged in a durable plastic container.
*Application Notes: The Moongel Damper Pad can be cut to any desirable size for those situations that call for a minimum amount of damping. 4 little squares under each corners of the APM is the best. You will have enough to share with 3 of your firends! Because it's non sticky you will need to fasten the APM with elastic rubber band. Please inspect before every flight.
See second picture for actual application.