Aramith 2-1/4" Regulation Size Billiard/Pool Ball: Jim Rempe Training Cue Ball with Instruction Manual Regulation size training cue ball is crafted from the highest quality phenolic resin which provides exceptional scratch and impact resistance; Measures 2-1/4" in diameter Marked with rings and targets on the surface of the ball developed by American Professional Pocket Billiards player Jim Rempe, who was inducted into the BCA Hall of Fame Allows you to practice judging the effects of very particular amounts of sidespin, topspin, backspin and other forms of cue ball control Intended to help players of all skill levels improve their game; One side is designed for beginners and the opposite side provides instruction for advanced players Includes a 56 page instruction manual which provides instruction on how to properly use the training patterns and offers additional tips and tricks