Review on Mann-Filter CUK 8430 Cabin Filter with Activated Charcoal: Ideal for BMW Models by Edgar Gomez

I held this filter up to the light and saw small but noticeable holes in the ridges that let large particles through easily. Quality filters are not the same. An advantage of such a large filter is that you can have very fine filtration that would normally restrict airflow, but the large surface area ensures adequate airflow. I put back my old dirty filter which filters much better than this one (dirty air filters don't filter worse, they just have worse airflow).