Tamiya Mass Damper Set (Heavy)Make sure your car gets firmly back on the track if it goes airborne after tricky lane change sections: these mass dampers will ensure that your car experiences less "bounce." Not only that, they help stabilize its vertical movement at high speed, reducing the chance of it leaving the course. The weight's range of motion can be adjusted with the hex nuts and spacers, or it can even be fixed in place. Each weight is 8. 8g.