For Version 2 Gearboxes
Has an o-ring on the back
These high quality cylinder heads have double o-rings to provide the best air seal possible. They will perform similiar to extremely popular brands at a fraction of the cost. Professional installation of this product is highly recommended. Airsoft Station offers installation of most parts by professional airsmith technicians. For inquiries regarding installation of replacement and upgrade parts as well as other airsoft services please contact our tech department here.