Abstract: A device for indicating to a golfer that the golfer's target control arm is being bent during a golf swing comprised of a housing having an electrical power supply and associated circuitry including a buzzer or light for generating a signal connected to a moveable member mounted by a hinge on the housing having an electrical contact disposed at one end. The moveable member and the housing are strapped about the golfer's arm that delivers the target control stroke such that the hinge axis is aligned over the elbow of the arm which is to be maintained in a straight line position during the golf swing. In addition, an illuminating device includes a cord which may be plugged into the housing such that the illuminating device may be positioned within the vision of the golfer during a golf swing to illuminate whenever the golfer's arm is not maintained in a straight position throughout the swing.