This trailer Ez jack is great for changing tires on a tandem axle trailer. You do not have to fool with getting out your crank up jack and laying under the trailer to raise up the bad tire. Ez Boat Trailer Jack is manufactured by Blaylock Industries and features a cast aluminum construction and is rated to hold 20,000 pounds. On a tandem axle trailer all you do is place the Ez Jack in front of the good tire and pull forward on to it. As the good tire rolls on to the Ez Jack it will lift the bad tire so that it can be changed. When flipped over, the Ez Jack makes a great wheel chock. You will find many uses for the Ez Jack, including the ability to level your RV when on uneven surfaces.