This is a high-tech device with a module that attaches to your putter and is aimed at a modular target. Lasers provide immediate feedback for three key components of putting: alignment, square face at impact, and stroke tempo.

When the module shows that you are correctly aligned, your eyes will start to recognize and appreciate what part of the putter appears to be aligned correctly. For example, your eyes might see the middle line on your putter as pointing to the left, yet the module says the putter is correctly aligned. Now you can attempt to discover what other aspect of the putterhead yields a correct perspective to your eyes.

I often find that a player perceives correct alignment more with the leading edge of the putter, or with a back line, or even with the two back lines, than with the center line. But the key here is what part of the putter your eyes can focus upon to trust the alignment.