GOOFIT 57.4mm Piston Assembly Kit for GY6 150cc ATV Moped Scooter 157QMJ The item fits for GY6 150cc Engine The piston diameter:57.4mm,pin diameter:15mm; The length of piston pin:42mm Arrival within 1-2 days (Sold by GOOFIT and Fulfilled by Amazon) Arrival within 7-15 days (Ships from and sold by GOOFIT)