Airsoft CNC Aluminum Double O-Ring Bore Up Ball-Bearing Silent Piston Head for GelballBlaster AEG CYMA Tokyo Marui Ver.2 Gearbox - AliExpress Sports & Entertainment
ASG Ultimate Upgrade CNC Aluminum Double O-Ring Cylinder Head for Airsoft AEG Gearboxes (Type: Version 3) - US Airsoft, Inc.
Super shooter Aluminum Double O-Ring Bearing Piston Head (Advanced Type)
Magic Box Ultra Seal Ball Bearing Double O-ring Piston Head for AEG | Airsoft Megastore