Most trailers purchased from us are tandem axle trailers, which means they have two axles. As required by law, all of our tandem axle trailers have 4-wheel brakes, a 7-way electrical plug that connects to the tow vehicle, and a 2 5/16-inch hitch (which requires the tow vehicle to use a 2 5/16-inch ball). Your tow vehicle will also need an electronic brake controller installed.