Low temp solder blow out plug, original and my upgrade version.
Allows you to use the blow out for a fuel return port if you have no other port options.... and I don't.
I also installed a "T" fitting with a 10PSI pressure relief. Makes it safer than OEM set up. If a fire hits my fuel tank side the tank will begin depressurizing before the low temp solder drops out. Buy a couple extra minutes to flag a ride before it reaches Allah Akbar temperature.