Fps Ergal piston head with bearing for electric gun (hi flow)

New enhanced flow Ergal dual oring piston head with ball bearing
new ventilated system by frontal surface design
this set will detect the air flow from the middle of the head pushing it to the bb
making your gun shooting faster even without changing the spring
ball bearing support and retain screw are included
ideal for marui/g&p/king arms aeg etc...