The trick on a jack for a typical tandem axle trailer is that it should be able go very low to reach under an axle with a flat tire. The best I have found is to go to a Dodge junk yard and ask for a 1988, or so, Dodge Dakota jack. They are a gear driven scissor jack that goes down real flat and the crank is a one piece fold out device that hooks into the jack in kind of a locking fashion so you can position the jack using the crank. The gear drive gives them a lot of lifting power for such a little jack. My $.02