GIVI E125 Set of 4 EXTRA CARGO Universal Rings with screw and sealed gasket. For installation it is necessary to identify a flat surface of the case, first drill a through hole with a diameter of less than 10mm, and then enlarge it to 10mm. Once the ring has been positioned, the gasket interposed in the internal part and screwed the screw, the system will be perfectly waterproof and will guarantee a solid grip on nets and elastic cords. You can install these rings on top case or side case in plastic or aluminum. You must find a flat zone on the case surface, then you can drill a hole and enlarge it until 10mm. Done this, you can put into position the ring, and in the inner part of the case you can insert the sealing and the screw. You have obtained in this way a water-resistant assem.