This AutoMeter Low Pressure Fuel Isolator is required when running a carbureted engine with a mechanical fuel pressure gauge mounted in the vehicle's interior. This isolator assembly mounts between the gauge and the fuel pressure port on your regulator or carb feed line and translates fuel pressure readings to the gauge keeping flammable materials out of the passenger compartment. This red anodized aluminum version from AutoMeter is safe for competition use, NHRA approved, and includes fittings to connect to -4AN braided stainless lines as well as a handy mounting bracket for installation.