The ARB BASE Rack kit (72in x 51in) is a fully assembled roof mounting system that uses a dovetail extrusion around the perimeter and internal beams to deliver wide accessory compatibility. The dovetail lets you clamp on lights, rollers, recovery boards, jack mounts and more without disturbing other loads, and resists dust buildup. Extruded aluminum beams with rigid internal bracing and a textured black powder-coat finish streamline wiring and mounting while providing a ready-to-fit platform.