These work OK, but were not robust enough for a work project I bought them for - a small conveyor system. I broke many of the plastic snap rivets just trying to assemble it - My 3" wide track was very poorly cut all along one side, there were many uneven snips and frays of plastic that caused the rivets to seat poorly. I did get it together after cleaning all of the edges, replacing bad connections with long bolts and nuts. Works fairly well when assembled and powered by a small gearmotor.