The Raptors Air Nozzle is a high-end upgrade part that increases air compression by minimizing the air leakage caused by standard stock air nozzles. Raptors has manufactured these air nozzles with an internal O-ring that provides the best seal between nozzle and cylinder head. Stock air nozzles are often made from plastic and wear out with use. These metal air nozzles are built to last. 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 the Airsoft Station Tech Department here.</a