Attaches to throttle shaft in the pictures (part numbers 13-2129 and 13-1894). 
Bolt on throttle swivel extension for throttle control and a smoother rotation. This kit adds 1/2” more throw to the throttle cable for throttle control. It is very smooth as the cable pulls in the center of the swivel that is housed on both sides rather than just one side. Very nice setup compared to the stock Tillotson swivel design.