Perrin's Afta-MAF silicone air box hose for the WRX and  STI features a 5-ply silicone construction and vibrant color. Replacing the stock corrugated rubber hose between the turbo inlet and factory air box will allow for improved airflow due to higher internal volume and smoother airflow due to the smooth interior. This product is the perfect compliment to a Perrin turbo inlet hose. The Perrin MAF hose is designed for use with the stock air box, but will work with any intake designed to use the stock rubber hose.