Set of 12 premium-quality ceramic balls made from extra-hard Si3N4 silicone nitride ceramic. Significantly improves differential lifespan while reducing friction and vibration. Higher RPM capabilities. High-speed ceramic diff balls have very high durability (when properly lubricated) due to reduced slip and heat. With ceramic being approximately 60% lighter than steel, ceramic diff balls have a significantly lower rotating mass. Together this means that the lifespan of ceramic diff balls is 3-5 times longer than that of steel diff balls under matching conditions. Ceramic diff balls have vastly-superior corrosion resistance over steel diff balls, and with an inherent low-friction coefficient and smooth surface, frictional forces on ceramic diff balls are much lower.