This is the stock fluid used in Subaru STI models. Until now, the Subaru Extra-S gear & Transmission Fluid was only available in a 5 Gallon Drum. It's superior design helps to lessen the common 3-4 shift grind in higher mileage 5 speed WRX transmissions. This fluid will work in any Subaru that requires 75w90 fluid in transmissions and differentials. Customers have reported that shifting is smoother and less prone to grinding with Subaru Extra-S fluid. It's what Subaru uses and recommends.