The Cuesight Precision Training Ball was developed for the specific purposes of teaching cue ball control and how to apply the proper "english" to the cue ball. The precision side allows you to learn to hit the ball exaclty where you intend to and to demonstrate the minute variations of spin. The spin side lets you develop the aiming and muscle memory needed for greater accuracy and consistency by using your cue tip as a measuring tool, with each line spaced 13mm apart. Both sides show a "safe area" within a red circle to better allow for visualization of how far away from center you can strike without a miscue. This item works well in conjuction with the Cuesight Laser Cue which projects the "bulls-eye" laser pattern directly on to the training ball, further allowing you detect and correct any noticeable variations with both your stroke and your aim.