4 pack High flow transfer port , this pack includes 4 transfer ports ranging from the size of 1mm, 2mm ,3mm , 4mm, they are puck design with pre inserted o rings for a great seal , please ensure to keep your gun within the legal limit of 12ft/lbs in the uk, do not attempt to tinker with air rifles if your not a trained competent person e.g gunsmith. Installing these alters the air flow you will get behind the pellet so adjust regulator accordingly to keep within the legal limit for the uk.
eBay