This tool is necessary for the fitting and removal of the nut that holds the fuel tap on the inside of the Vespa fuel tank. The straight design is used for the PX/T5/Cosa/PK models and the curved model in the V50/VBA/VNA models fuel tanks. The GS160 and SS180 Vespa models require another adaptation of this tool. Check the exact location of this fixation nut using an electric torch...