Abstract: A device that provides feedback to a golfer on the characteristics of their swing of a golf club. The device can be mounted to or incorporated into the head of the golf club and includes a first light source and at least a second light source. The first and second light sources are aligned such that an imaginary line bisecting the first and second light sources passes through the sweet spot of the ball-striking face. When the club head is at the address position, the imaginary line lies in a horizontal plane and is further preferably at right angles to the ball-striking face in that plane. The first and second light sources are visible to the golfer when using the golf club at least at the time when the club head is striking the ball. The first light source has a first turn on/turn off cycle pattern and the second light source has a second turn on/turn off cycle pattern that is different to that of the first light source.