Autometer Phantom 2-5/8 fuel pressure gauge question

Hello all,

So I have one of these mounted by the wiper cowl on the outside of the car and when I went to hook it up I noticed a problem. I am missing the part that connects to the fuel rail on the motor. Does anyone know where I can purchase a new one or perhaps have a part number for me? Please let me know either way. Thank you.

William Kramer