Empire USA Replacement Training Cue Ball, 2.25-Inch One of our best quality training cue ball, each dot on the cue ball is there to assist the billiard player to aim the cue ball and get the best result for training purpose Made by high quality resin, each ball are polished to perfect balance of roundness, each ball are made to 2-1/4" which is the standard size worldwide Each ball are made to 2-1/4" which is the standard size worldwide