Review on 🔧 Camco Olympian Aluminum Stack Jacks - Stabilize, Level, and Position RVs, Trailers, and Campers - Up to 6,000 lbs Capacity - 17" Extension - 4 Pack (Model 44560) by Terrance Castle

Quality can't be beat at this price. Seems to be nicely made. The only thing that confuses me is that it needs a locking mechanism underneath. The screw thread in the base is just a large steel nut that fits into the cast socket. The problem arises when you need to expand the screw to its upper limits. The assembly may wobble slightly as the steel nut is not tightly secured in the base. The solution I came up with was to buy another steel nut and screw it in from the bottom once the jack is set in the desired spot. With a nut on both sides it will be tight. Since it's difficult to get my fingers in there, I welded extension tubes to the bottom nut for easy finger tightening. It doesn't really need to be tightened with a wrench, just finger tighten.