This is the hollow bolt that goes on the top of the fuel filter. It has a restrictor in it. It is used with a banjo style fitting on the end of the plastic fuel line.
Rebuilt Diesel Injector for 1.6l NA Diesel Vanagon
Rebuilt Fuel Pump for Diesel Vanagon 1.6l
Diesel Injection line
Injector Heat Shield
Retainer Ring, Fuel Filler Cap, Diesel, Vanagon 80-92