Bulkhead quick connector QCK-3/8-PK-9-B Female thread with sealing ring. Nominal size=8 mm, Type of seal on screw-in stud=Sealing ring, Assembly Position=Any, Pneumatic Connection=(* M16x1, * PK-9 with union Nut), Materials note=(* Free of copper and PTFE, * Conforms to RoHS)