need help with air/fuel gauge and fuel pressure gauge please
 

Ok so I got 3 gauges.. air/fuel boost and fuel pressure.. I have all wires Connected except the green wire for the o2 sensor. there is 3 wires comin outta my o2 sensor n don't wanna just start slicing... the boost gauge is good.. and the fuel pressure gauge I don't kno where to connect it.. this is the only piece I have.. if anyone knows wat other fitting I need that would be awsome
https://cimg5.ibsrv.net/gimg/mustang...e549f9182d.jpg

Thanks in advance

that would thread into the shrader valve on the fuel rail. You will need a male to female adapter fitting as well.