Extra-S gear oil is what Subaru uses on all its high-performance models. According to Subaru, this fluid has the following benefits:
One quart bottle.
Nomenclature note: Subaru used to sell a drivetrain fluid called "Extra S" that came only in five gallon pails. The five-gallon pails were discontinued and Subaru started offering this one-liter bottle instead. Subaru of America tells us this is the exact same fluid as the old Extra-S, which is why we advertise it with the Extra-S title.