The K&N AirCharger 63-1101 air intake system replaces the restrictive factory air filter and air intake housing in some Ford Focus models. K&N intakes are designed to dramatically reduce intake restriction as they smooth and straighten air flow. This allows your Focus's engine to inhale a larger amount of air than the factory air filter assembly. More air means more usable power and acceleration throughout the engine's RPM range. The 63-1101 air intake comes with a K&N XStream Top air filter designed for higher air flow and durability. It directs air through an aerodynamically engineered intake tube into the engine's throttle body for a guaranteed power gain. The XStream Top air filter can be used for up to 100,000 miles before servicing is needed depending on driving conditions. This air intake is relatively easy to install using commonly available tools. This air intake cannot be sold in California. It is not legal for use in California or other states adopting California emission standards.