High Temp/Gasoline Submersible Wire
Keep in mind though...
The minute you cut the wire to add a terminal, spade connector, etc, I would assume the gasoline submersible rating goes flying out the window.
Suggestions:
Not sure what you are trying to do but likely if its an OEM gauge and OEM installation, there is probably an OEM part that accomplishes what you are trying to accomplish, and is probably very much worth the extra coin instead of gambling with fuel and fuel vapors (even though I am well aware there are other safety mechanisms in place to keep your car from detonating in place, ie gas cap).
If it is aftermarket, I would probably call the supplier and ask them what they recommend doing to complete your installation.

