Simple to install and easy to appreciate, the AFTA-MAF is an eloquent compliment to every engine bay. Replaces the factory corrugated rubber hose between the inlet tube and air box. This is an awesome part for restoring a high mileage or older WRX or Legacy GT that very likely has developed cracks or holes in the original part. These cracks will cause the engine to run poorly and get bad gas mileage amongst other things.