Does this gauge fits in the Air venturi 7/8 unf valve?
No. It only fits the Air Venturi G6 hand pump
does this gauge work for benjamin corbon fiber 4500psi air tank?
Will this fit the Air venturi inline gauge??
No, the inline gauge manifold on AV-00031 has female 1/8" npt thread. This gauge is 10mmx1
What is the thread size and is it NPT or BSPP?
It is metric 10mm x 1
What is the diameter?