JR MASS DAMPER BLOCK DESCRIPTION Mass dampers are resonant devices used to suppress or absorb vibration. When installed properly on a Mini 4WD machine, they draw away vibrational energy from the machine and dissipate it internally; reducing the motion of the car and helping it maintain speed and cornering efficiency. • Brass mass damper have a black plated coating. • Weighs 8.3g • Each item is compatible with any Mini 4WD or Mini 4WD PRO car.