This is a package of ten 3mm 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: Ten 3mm diameter Ceramic Differential Balls REQUIRES: Installation SPECS: Diameter: 3mm kpm01/02/2007 ir/jxs