I brought four of them as the price is cheaper, it works well on level ground, but one day when I park my RV on driveway with a very little degree slop, after a few days, I found the RV moving its position and the wood under the front jack was be pushed to front, that's not safe,
I think this product is fit small/light weighted RV and on level ground but not on medium/big size RV and unlevled ground.