The Putting String Line is a simple way of gauging whether your stroke is on track. By setting the 1st peg central to the back of the hole then pulling out down the line of the intended putt and putting in the 2nd peg. Now you have a line down the centre of the straight putt. With the string line line now set above the ball and the putter you can line your ball up underneath the line and your putter. Now stroking the putt as normal you can see whether your putter is tracking inside or outside the line. This gives you instant feedback on what you need to work on.