Orange plastic snap-on attachment used for chipping and putting to indicate any change in the relationship between the player's hands and clubface.
The Wrist Brake attaches anywhere along the shaft by typically somewhere above the middle of the shaft will allow you to monitor the shaft's angle. The product has been designed so the arm can come out and rotate to accommodate offset putters or wedges. Square the arm to the putter or club face and it is very easy to see unwanted wrist movement.
The product is an excellent way to train players how to keep the arms and body working together to produce solid consistent ball contact with good distance control.