This is a screw on oil funnel for the FA20 engine in the 2015+ Subaru WRX. It also works on a 1997 JDM ej20k so this very likely works on any Subaru engine out there.

Just take the cap off and this fits into the oil filler neck. This funnel is extra thick and should last a long time and be tough to break. Maybe the straw helps maybe it doesn't but it cannot hurt having a dedicated place for air to escape.

I have provided 2 models here. The first one has a single straw to allow air to flow up and back out of the engine to aid in filling oil. This was the whole idea behind making this funnel in the first place.

The second model takes this principal and turns it up to 11(okay, technically 6) because if one air pipe is good then 5 more has to be better, right? Totally.