Gear differential inside gears accuracy produced from new graphite composite mixture. Includes 2 bevel gears + 4 satellite gears. Molded from an all-new unique lightweight and extra-strong graphite product provides gears an optimal security of hardness, toughness, and freedom to provide stamina, minimal usage, and minimizing breakage or teeth stripping. The lighter, graphite gears end in increased drivetrain effectiveness. A must have for expert racers. Fits XB4, NT1 & T3 cars.