Ann,
Are you looking for a motorized (electric) tongue mounted wheel to move your trailer into a tight spot?
If so, this may be what you want:
http://www.eztug.com/ It is very helpful in moving our trailer to its parking spot at home, behind the tree, between the shrubs and avoiding the eaves of the garage, into a ridiculously tight spot to conform with zoning requirements .... impossible to back into because of angles, even pushing it with the atv. We usually take the wheel off (easily) when traveling, because the wheel extends out so far, and is cumbersome in tight turns.
Because of where we keep the trailer, and the fact that it took three to four people and thirty minutes to (manually) push it into its little spot at home, and our sore backs later, the ez tug was well worth its initial cost. We wired it to the trailer
battery.
Sherry