This fitting is a straight M12x1.0 Female to -4an Male fitting. These are used in our FA20 turbo oil feed line kits to adapt to the factory oil hard line. Additionally these can be used directly off an EJ factory hard line to adapt to 4an if you are building a custom oil line kit. This is a bit of an obscure fitting as it has a 45 degree taper on the female side instead of the 37 degree norm for an fittings.
This is made from stainless steel for longevity and corrosion resistance.