I use the EyeLine Putting Alignment Mirror for all my putting lessons. It gives instant feedback to my students so they can identify the proper putter face aim, alignment and eye position over the ball. In addition, you can use the putter gate slots with tees to assure the putter face is square through impact.
The EyeLine Putting Alignment Mirror is the perfect tool for checking all parts of your putting setup, alignment and putter face position at impact.