FPS dampered ventilated piston head w/ bearing

New quality made of POM and fiber glass
special shape to reduce friction and optimize the air floss
the special cone shaped allows the oring not to cover ventilation while air charge
this will makes the piston head to eject the same air quantity on each bb making the gun more accurate
radial ball bearing oir rubber oring pad are included (use the rubber to reduce mass weight especially in hi speed configuration)
for marui/g&p/ka aeg and compatibles electric gun rifles