Heavy Duty Cantilever Internal Truck Trolley Assembly completely enclosed in International Gate Devices EZ Slide Aluminum Track assures easy, smooth sliding performance in all weather conditions. One piece, heavy duty, cold rolled, zinc coated steel body. Steel side guide wheel with permanently lubricated sealed bearings provides free lateral alignment control from within track. Factory lubricated, rubber sealed bearings, provide maintenance free operations for the life of the gate. E/Z Slide is designed with NO exposed roller wheel for added safety. Eliminates the chance of fingers or hands being crushed if children hang on your slide gate. Also eliminates dangerous pinch points that are common with cantilever rollers.