Clutch nut hardened -BGM PRO M10 x1.50 (standard) SW=16 half-high- used as clutch nut Vespa for standard auxiliary shaft V50, PV125, ET3, PK S, PK XL - hardness 10

Clutch nut -PIAGGIO- Vespa V50, PV125, ET3, PK S, PK XL - (used as nut for gear cluster)