The K&N Drop-In High-Flow air filter for 2006–2010 BMW 135, 335 and 535 models replaces the factory element with washable, reusable layered oiled cotton media to improve airflow while capturing contaminants. It installs into the stock air box as a direct replacement and is backed by K&N's No‑Hassle Lifetime Limited Warranty. Reusable design also reduces disposable-filter waste.
K&N 06-09 BMW 135/335/535 Drop In Air Filter