One of the most critical aspects of the golf swing is the position of the head during the swing. Many professional golfers and instructors will tell you keeping the head still during the swing is absolutely critical. Others say some lateral motion is normal. In any case, head motion is hard to detect during the swing. The Head Motion Indicator (HEMI) Rod enables you to see this motion very easily and accurately.
Simply stick the HEMI Rod into the weighted base so the Viewing Frame is about even with the knees. Place your ball so you can see it through the Viewing Frame.
Now you can hit the ball while viewing it through the Viewing Frame and see any head movement during the swing.