SEAT Accessories provide several fastening systems for use in transit. Over the roof bars or inside the car´s boot, this fastening strap kit skeeps everything properly secured. Reference: 000017770 For light load transportation; includes 2 wide and 2 narrows straps with tensioning mechanism to fix objects onto roof bars or inside the boot.   Reference: 000017771 For securing heavy loads; includes a hook and a tensioning mechanism to carry loads securely and effortlessly.