K&N Performance Intake Kit for Ford C-Max/Focus II / Volvo C30/S40/V40/V50/V70 / Mazda 3/5

The K&N 57S-4000 Performance Airbox is built with an injection molded lid featuring an embossed K&N logo, designed to significantly reduce airflow restriction compared to your stock air filter and lid. This allows your engine to draw in more air, which translates to more usable power and improved acceleration across the entire RPM range. The kit includes an oversized, high-flow conical air filter that can go up to 100,000 miles before needing service, depending on your driving conditions.

This performance air box is designed for a relatively straightforward installation into the factory air box base using common tools. K&N backs this system with their Million Mile Limited Warranty, indicating they build these intake systems to last for the life of your vehicle. While this specific kit is not CARB approved and cannot be shipped to California, it offers a notable improvement in airflow for your Ford Focus.