This bore-up air seal nozzle from Guarder is made from acetal, and features an internal o-ring to enhance the air seal between the nozzle and the shaft of the cylinder head.

This nozzle is designed for M4 series guns.

This is a bore-up part, with a larger inner diameter that allows for greater air displacement by the piston. This nozzle will only fit on bore-up cylinder head shafts.