REESE Towpower 5/8 In. pin and clip is designed to fit Class III / IV, Reese 33, 36, 36, 37, 44, and 51 series hitches with 2 In. hitch boxes. This pin is 5/8 inch in diameter and includes the spring cotter pin. The PVC comfort grip is designed to protect the hands and allow for a better grip while inserting or removing the pin and clip.