Looking for info on a hitch pin?

A while ago I remember seeing a hitch pin that was partially threaded half way and u inserted the pin through the 2 in receiver and whatever u r towing and than it had a nut that u could tighten up and secure it to the hitch. Than it had a hole for a hitch pin.... been looking on line but nothing comes up.
Anyone know what I am talking about and knows the name of it so i can do a search for one? Hope I explained it right.
thanks