I used eight of these in strategic locations under a 28 foot 5th wheel RV that was moving up and down with each step anyone took inside. They're not made to jack but to stabilize, so when leveling the trailer, be sure to use a hydraulic jack and then put this unit in place snugly and then lower the hydraulic jack. Use a level on the floor to verify your front and back and side to side level readings. Walah! No more bouncy floor.
Rating: [5 of 5 Stars!]