The McDermott Jump Trainer Cue Ball will teach you 9 jump shots to master with one easy solution. Learn Standard Jumping, Jump Draw and Jump Follow plus add right and left masse to all your jump shots. This easy to use training cue ball measures 2 1/4″ and comes with written instructions right on the ball. Learn how to get out of those tight spots and win more games with McDermott’s Jump Trainer Cue Ball.