Abstract: In order to help a golfer to develop "muscle memory" for consistently executing an ideal swing, there is provided a grid plate on which is defined a ball contact zone. Enabling the golfer to see the head of the club as it is swung through the contact zone is a battery-powered L.E.D. mounted on a Velcro-fitted wrap-around jacket. By installing the jacket on the club head and illuminating the L.E.D., instantaneous visual feedback is provided so that aberrations from the ideal path defined by the ball contact zone are detected, interpreted and can immediately be corrected in subsequent swings. Both the jacket and the grid plate possess special features helping to protect against the harmful results of forceful, inadvertent impact between the clubhead and the grid plate.