The Line-M-Up Pro provides multiple marking options allowing you to sink more putts, hit more fairways and save strokes instantly. It also gives you a visual guide when putting. When a good stroke is made, the line on the ball appears straight as it rolls. When poorly struck, the line will apear to wobble. When a pure stroke (no wobble) with the proper speed misses the hole, you can identify a missed read to improve your green reading skills.