Complete cylinder head for 50cc 139QMB / QMA engines. Unlike many other available cylinder heads, this is a complete head. That means: valves, valve springs, valve shaft seals etc. This head is ready to install, with no need for grinding valves or fumbling with springs, or specialist tools. Dispatched without SLS. This can be blanked off, which leads to quieter running and slightly more torque. Cam shaft and rocker arm assembly not included. Delivery as shown.