This optional NEXX Racing Ceramic Ball Differential for the MR-02, and MR-03 Mini-Zs offers drivers a longer lifespan differential thanks to it's use of ceramic balls. The included spur gear is a 53T size, with a 64P tooth profile. Built with a stainless steel (SUS 304) shaft, 8 ceramic balls, polished pressure plates, and gold anodized 7075 components, this upgrade will not only offer improved performance, but also take a beating thanks to it's build materials.