This is a package of twelve 2.4mm Ceramic Nitride Pro Series / Differential Balls from ACER Racing. / / FEATURES: Ceramic Nitride construction, black in color / Grade 5 diamond polished for low rotational mass / 79% lighter than Tungsten Carbide and stronger / Each pack is matched for consistent concentricity, roundness and / smoothness / will not melt or shatter under extreme racing conditions / / INCLUDES: Twelve 2.4mm diameter Ceramic Differential Balls / / REQUIRES: Installation / / SPECS: Diameter: 2.4mm / / mlm 5.8.07 / ir/jxs