This seat bench is installed as an original part on the Vespa Primavera 125 - 70th Anniversary Edition (color light blue), but also fits the "normal" Primavera and Sprint models.
The seats of the Primavera/Sprint 125/150cc models can be exchanged with each other, but do not fit the 50cc models due to the electric seat release.
Conversely, the seats of the 50cc models do not fit the 125/150cc models due to the manual seat release (using a lock and key) but can be exchanged freely between Primavera 50cc and Sprint 50cc models.