If you want to struggle, like I have been struggling for almost 5 months, to make it work properly on a 10-inch beam, then go ahead and get it. Firstly, there is an adjuster under the bearings that holds the whole system in place to roll properly on the beam. No matter how much you adjust and tighten it, it comes loose and the system goes wherever it wants, just like a belly flop. It also sticks to the beam and skids. If you tighten it enough, it skids, if you leave it a little loose, apart from going like the back of a belly flop, it skids again. All this creates another problem with the trolley, which is that the trolley leans forward under the weight and as it pulls the load, the wire rope wraps exclusively around the front part of the trolley, causing one wrap to ride on top of the other and occasionally slip, with the risk of being cut by the shaking it does. I hope this helps you because those who sell it, apart from the fact that some may not actually know how it works, there are others who act like "germanos."

~The review is for the Electric Trolley, not the manual one.~
For the manual one, I can only say that I would not trust this company again.