Regulation size training cue ball is crafted from the highest quality phenolic resin which provides exceptional scratch and impact resistance Marked with a red circle on the surface of the ball which allows you to check the placement of your chalk mark, helping you achieve a consistent cue stroke Adheres to the most stringent specifications in the industry to ensure each ball has the right density, balance, diameter, roundness, glossiness, hardness and weight Intended to help players of all skill levels improve their game; Measures 2-1/4" in diameter