Flywheel SERIE PRO by BEEDSPEED, for Vespa 50-125/PV /ET3/PK50-125/S

can I choose the 19mm or 20mm version? It works on ET3 without any mod? I red 12V in description, so this flywheel will do 12v with the original stator plate?? I don't want to change lamps... Thank you.

 

ART NUMBER 17945000