"I love these things!!!!! I travel for work and live in my trailer most of the year. I was truly amazed at the difference.   The problem is they look gimmicky I was skeptical even with the recommendation of the guy from the RV parts store. Till I put them on my Trailer I'd recommend you give a slight discount in sets of three as that's what needed to make your trailer pretty much immobile.   My hats off to you for making something that's simple and works great at a reasonable price." Robert Love.