Schwintek/LCI makes 2 types of geared slides. One that attaches directly to the side of the slide and has serpentine gearing and one that is spaced away from the slide and looks more like a rack. Numerous problems have been reported with the first type as it requires the tolerance between the slide and the opening to be very tight. Putting this type on the longer/heavier slides just makes the problems worse. They do work ok on smaller slides like closets that are either not heavy or do not extend too far. The rack style are far more forgiving and work much better for bigger slides but they are still not a perfect solution. Many manufacturers are now mixing the styles on the same rv depending on the size of the slide.