Often we receive inquiries on "9/16 female" fittings.

The standard 9/16 female does NOT fit everywhere, please have look to some pics here. We hope they are self explaning



On the regulator style UNF 9/16 a standard female 9/16 fitting may NOT seal safe!

You see the o‐ring is NOT proper in the shoulder of the female adapter, also below is still threaded

part, this o-ring can never seal safe and correct!!

Compare it to a proper male 9/16 fitting. It closes and seals correct and safe



For regulator style male 9/16 threads it is safer and better to use an inner sealing system with a stem

an free rotating nut.


Also for a QC6 for example connected to such a male 9/16 UNF....a stem style fitting is needed!

This seals nice and safe....