The brass thingee is the adapter you will need to safely install a fuel pressure gauge in your dash (mechanical gauge). The gauge will read raw fuel pressure upstream of the TBI regulator, which is what you really want. if your fuel pump starts south of Terra Del Fuego, you will know it instantly. You might have time to get to a repair shop before it completely craters. I will run copper tubing to the diesel isolator (transducer) mounted somewhere in the engine compartment, and run tiny little plastic tubing from the diesel isolator (transducer), through the firewall, and to the gauge in the dash. No fuel inside the coach, and no way to get there.
More pictures to come as I finish the installation.