These high-quality aluminum wheels feature deepened rims, and are around 7 grams heavier than plastic counterparts, providing natural damping for your Mini 4WD racing machine and make it less likely to fly off of the track. As a further bonus, they will lower your cars' center of gravity for noticeably smoother laps. Try fitting them to the front or rear of your car only, to adjust its characteristics. Set Contents - Aluminum Wheels for Low-Profile Tires x2 - PP Wheel Bushings (White) x4 - One pair of wheel weighs approximately 9 grams, roughly equivalent to fitting 2 standard mass dampers (plastic wheels typically weigh 2-3 grams). - Recommended for use with reinforced shafts. - Compatible with cars using low-profile tires.