That's a good point; I've struggled with keeping my arms quiet in the downswing so I hoped that the Momentus would help me to "feel" the correct downswing.

Imagine my surprise when it turned up yesterday, and on the video that accompanies it Jim pronounces that the most effective way to downswing is to "push down and toward the ball with the right hand"! Seems contrary to all the good advice on GTO. Oh well, I'll try it and see how it goes......