To keep a consistent arc throughout the swing which allows the club to meet the ball at the bottom of that arc every time, we need the left arm (for right handed golfers) to stay straight throughout the entire backswing, downswing and at past hip height on the follow-through. Backswing: This product gives you instant feedback by making a clicking noise as soon as the arm bends on the backswing. Work on this until you can swing back without clicking. Downswing: Again, the TacTic will click as soon as the arm bends, allowing you to know if and when this problem is occurring which helps you correct it. Follow-through: This is where the TacTic Arm Aid comes into its own. Most golfers who top, hit the ball along the ground or slice have a problem with the infamous "chicken-wing" allowing the lead arm to collapse. The TacTic Arm Aid gives you immediate feedback to help you keep that arm straight throughout the hitting area almost immediately improving your ball striking. Mel Sole's Rating: 5 out of 5