This invention relates to a training aid 10, 100 for a golfer. The training aid 10 mounts to a golfer's cap 24 or sunglasses and includes a battery powered collimated light source 12 in the form of an LED which is configured to emit collimated, visible light. The aid 10 further includes an electronic circuit which comprises a microcontroller 17 which is drivingly connected to the LED and an electronic orientation sensor 16 which is configured to sense the orientation of the LED. The circuit and LED are housed within a housing and a mounting formation is provided for mounting the training aid 10 to a user. In response to an orientation of the light source 12 sensed by the electronic sensor 16, the microcontroller 17 automatically interrupts emission of light when the training aid 10 is orientated outside of a predefined operative angular range.