100% Pure Stroke teaches you to keep your putter face square to arc through your backstroke, at impact, and through release. 100% Pure Stroke simultaneously detects if you strike the sweet spot, and if your putter face is square to your intended line at impact. 100% Pure Stroke also detects if your putter face is square to arc on your backstroke, and if you have released the putter head square to arc through impact. Thus, 100% Pure Stroke trains you to strike the sweet spot, square the putter face at impact, and to be square to arc on both backstroke and release through impact. There are, however, several fundamentals that must be learned in order to achieve a Pure Putting Stroke.