"I purchase two Anderson 3604 Camper Levelers several months ago. It was a leap of faith because they are a little pricey. I didn’t have chance to use them for a few months after I purchased them.... I took them out of the box and figured out how to use them. It’s not complicated, but my wife was going to be the Anderson Leveler installer so we went over my expectations.
I back onto them, a set for each wheel, until our trailer was level. This is done by holding a level vertically on the side of our trailer. We drove up to a level of about 1” and then placed the smaller piece on the other side to lock them. It was great and an unknown benefit is that it helps stabilize the trailer.
You can get from about 3/4” to 4” of rise from the Anderson Leveler. If you need more than 4” to get level, find another campsite.
I recommend the Andersen-3604 Camper Leveler."