The BASE Rack takes accessories and cargo loading to a whole new level of simplicity, speed and personalization. One of the most versatile BASE Rack accessories, the Alloy Block Set Nut and Bolt Kit is a set of four powder-coated aluminum blocks that attach to the dovetail on any location of the BASE Rack. Configure your BASE Rack for about any cargo load with these must-have attachments. By incorporating a dovetail extrusion around both the full perimeter and along each edge of the internal beams, the BASE Rack provides endless mounting and attachment options. Adding, removing and repositioning accessories and roof loads is quick and easy with the BASE Rack's dovetail system, making it easier to install and remove individual items without disturbing the whole load. Plus, unlike traditional roof rack channels, the BASE Rack dovetail extrusion won't collect dust and debris. ;