Made of heavy-duty aircraft grade cast aluminum, the rocker-shaped EZ Jack Tandem-Axle Trailer Jack is designed primarily for tire changing. The trailer operator simply places the device rocker side up immediately in front the good tire then drives onto it until the tire to be serviced has cleared the ground. For a trailer with low fenders, the jack can be used in reversed position, i.e., rocker side down, for 2 inches of additional elevation. It can also function as a wheel chock when in reversed position, making it ideal for parking the trailer or chocking on inclines.