Complete ball-differential set uses new special Swiss 7075 T6 aluminum which is 30% stronger than previous material. Features heat-treated and hardcoated aluminum output shafts, screw for external adjustment, tough composite 34T diff pulley with Labyrinth Dust Covers™, high-performance ball-bearings, high-quality carbide axial thrustbearing, heavy-duty diff washers, and carbide diff balls. Factory pre-assembled.