Trailer hitch receiver size.

If your Explorer has the optional factory-installed trailer towing package, then you have a Class III hitch receiver. You can recognize the presence of a towing package by the fact that the electrical connector mounted beside it has 7-pins. For what it is worth, I believe that the opening is 2" square, but that is not how you specify what hitch (technically a "ballmount") you need. "Class III" is the magic phrase.

If your Explorer does not have the factory towing package, then you have a Class II hitch receiver. The electrical connector has either 4 or 6 pins (I've forgotten which). I believe the receiver opening is 1" square, but again, "Class II" is the magic phrase.

You mentioned a bumper hitch, so I assume you are talking about towing something reasonably light. For this, you can get a very simple ballmount for either hitch at WalMart, or any auto supply store. Most light trailers take a 1 7/8" ball.

Bill Jeffrey

Well, just because a truck doesn't have a factory tow package does NOT automatically make it a Class II..

Aftermarket hitches come any way you buy them! That said, it's most likely a class III, but as others have mentioned a tape measure is your friend.

There's not a lot of choice (except for rise / drop ) but the difference in mounts is big enough that you should EASILY be able to eyeball it. A trip down Wal-Mart's trailer accessory aisle should enlighten you !.