Bought this set a few months ago for a planned project. Evaluating the details tonight, the rails, bolts, bearings and connectors seem ok so far, but the rail supports are GARBAGE! the holes for attaching the base are arbitrarily offset a few millimeters along the X and Y axes and discarded. If the supplier fixes this issue and can send me the correct replacement parts, I will change this rating. Otherwise be warned, at least part of this kit is GARBAGE.