This 2-post expansion kit converts our economy 2-post rack(FR1907-45-02LE) into a 4-Post Floor Mount Rack. These racks are constructed of heavy duty steel and are built with a tapped hole rail design. They are ideal for mounting of patch panels, hubs, routers, Audio/Video equipment and more. They have a black microfinish with numbered rack units, and come in a 7ft. height.