Check out any of the thirty 023 Number Plate Holder - Tail Light components enlisted.
The Screw Tcei M5x18 is the cheapest item from this partsfiche.
Parts such as the 023 Number Plate Holder - Tail Light: Lamp 12v 5/21w, Bulb 12v 10w Ba15s, O-ring 19.3x2.4, Nut are included in the Mts620 2006 Eu (multistrada 620) 9151-2261c 023 Number Plate Holder - Tail Light parts fiche.