These roller assemblies are constructed of steel brackets and plastic wheels and they're manufactured in a left and right-hand roller assembly. The roller assemblies are used to replace worn or missing guide buttons, allowing the drawers to glide easily when opening and closing, while at the same time preventing wear on the cabinets face frame or drawer opening. These roller assemblies install into the inside lower left and right corners of the drawer face opening with necessary fasteners provided within each kit. This pair of roller assemblies have a max load rating of 20 lbs. and they are used by many to replace missing or malfunctioning drawer track hardware. For a complete kit with track, guide and back plate, see Prime-Line part R 7137.