The XB2 ball differential is recommended for many XB2 designs whenever placed on very-low to medium-traction dust or clay areas to improve traction. The externally-adjustable ball differential is machined from HUDY Spring metal™ and it is hardened for extra durability and long lifespan. A high-quality carbide thrustbearing and carbide balls are included for ultra-smooth procedure. The ball differential comes factory pre-assembled.