GOOFIT 54mm Piston Ring Kit for 125cc Taotao Baja Roketa Horizontal Engine ATV Dirt Bike The piston diameter:54mm;The piston pin diameter:14mm, length of piston pin:40.8mm Fit for SSR BMS NST JCL Taotao Baja Roketa Kazuma Sunl Coolster Jetmoto and other unlisted brand There are 2 type of Chinese 125cc engine,this item fit for Horizontal Engine 125cc,not for vertical engine Arrival within 1-2 days (Sold by GOOFIT and Fulfilled by Amazon) Arrival within 7-15 days (Ships from and sold by GOOFIT)