You MIGHT wish to measure the height of the ramp vs the amount of clearance you have under your trailer FIRST before purchasing for this purpose.
Second, those ramps tend to be steep, may bottom out your trailer suspension and your other wheel will still be touching the ground or the ramp.
Third, would have to backup or pull forward totally straight, otherwise your leading wheel will start running off the ramp.
Forth, would need to ramp BOTH sides, otherwise risk an unstable situation..
Fifth, Ramping wheels to this extreme WILL overload one of the axles/tires.
Sixth, several bottle jacks or trolley jacks and jack stands WOULD be a much better way to go about this..
It isn't hard work to use a jack, why does everyone go to extremes and use tools that were not really designed for the job?