Mike - This is the one I used. It seems the o-ring is "new and improved" method of sealing the switch according to the description. I search the internet and they all have an o-ring. Also, I would suspect if its in to far and opens again as I shift into reverse, the light should come on briefly before going off. On another thread, Someone else had the same problem and they took the switch to a machine shop and had the face milled down. I would like to avoid doing this if possible.