Cabin air filters are designed to clean the air that enters a vehicle through the heating, ventilation, and air conditioning (HVAC) system. Cabin air filters absorb fumes, pollen, dust and pollutants from entering a vehicle and protects passengers from being exposed to these elements, especially those affected by allergies and other respiratory problems. Bosch HEPA Premium Cabin Air Filters are designed and tested to meet High Efficiency Particulate Air (HEPA) standards based on ISO 29463-3:2011 and provide filtration efficiency of 99.97% at 0.3 microns. This efficiency provides ultimate protection in trapping allergens, dust and other particulates that can enter your vehicle and provides the cleanest air possible for you and your family.