Originally Posted by fishboat

I have the 2 inch version and use a 2 inch hitch. Mine has a locking pin. (on mine, purchased last summer) The binding ball is just to tighten up the rack to keep it from moving around, not to keep the rack in the hitch. Maybe the design has changed before, or after, my version. I know there was a design that allowed a lock to be installed in front of the ball-tightening allen wrench insert. Mine does not have that.