This is an optional XRAY 1/10 Formula Car Gear Differential Set. This XRAY self-designed, revolutionary, super-smooth gear diff for 1/10 formula cars is a direct replacement for the ball-differential; it is a complete set which requires no other extra parts and no extra adjustments. Using the gear differential makes the car more stable and easier to drive, especially in high-traction conditions. The gear diff increases on-power steering which is needed on almost all types of tracks. A “must have” for every racer. The complete gear differential set includes a composite case and cover, precision-molded internal satellite gears made from special XRAY-developed composite material, all ensuring long lifespan and super-smooth efficient operation. A super-strong hollow steel shaft ensures maximum reliability and strength. The advantage of the gear diff is that it is maintenance-free. When the diff is correctly built, there is no need for maintenance for a very long time, no need for frequent oil changes, and no leakage due to a superior sealing system. Fully assembled gear differential is 2g heavier then the ball differential.