For those of you who want to keep your blade square, and also keep your putter on a perfect straight line during the putting stroke, here’s an aid which may help.
Dream54 Putting Aid
Industrial Putting Technology is the maker of the Dream54 putting aid. This aid features two bars which attach to two different stand options. The first option sits on top of the ground or your floor in your house. The 2nd stand option is a set of spikes which you can put into the putting green to mount the unit for practice on a real surface.
A guide unit mounts onto any putter with the main wing sliding between the rails. Once setup, about a minute or two, you can work on the “straight back and straight thought” stroke and also keeping the putter face square.
This obviously would not be a good device for those of you who use a swinging gate stroke, which is more arced and has the face opening and closing slightly.
Here’s a pic below of the rail setup #1 described above: