Includes Recharge Oil (8 oz.) and Cleaner Spray (12 oz.). The recharge oil traps the smallest dirt particles, ensuring your engine is breathing clean air. The oil creates a positive magnetic charge with the filter's stainless steel mesh. This positive charge attracts negatively charged dust particles entering the filter, clearing them off the cotton and allowing for maximum airflow. The oil also contains a swelling additive for the cotton filtration media - this allows filtration media to collect small dirt particles that could harm your engine.