The Putt Ruler by Greg “The Golf Guy” Jones is a putting training aid designed to help you develop the necessary skills to putt the ball on line. The Putt Ruler is marked in one-foot increments that correspond to various putt lengths. Start by putting the ball from the one-foot mark to improve the accuracy of your 3-foot putts. As your skill increases, move the ball further down the Putt Ruler until you can putt the ball the full 4-foot length, which corresponds to making a 12-15 foot putt. The Putt Ruler is lightweight aluminum and is easy to use indoors or outside. Learn to rule the greens with the Putt Ruler!