2-Pack H13 True Hepa +Activated Carbon 2-In-1 Filters | | Compatible With Blueair Blue Pure 311 Auto Air Purifier , Part Number F311Pacf105618 (Not Compatible 311 Air Purifier) | | H13 True Hepa Capture Up To 99.97% Of Airborne Particles As Small As 0.3 Microns. This Includes Dust, Pollen, Pet Dander, Smoke, And Other Minute Particles ,Activated Carbon Reduce Chemicals Vocs, Tobacco Smoke, Pm2.5,Common Household Bad Smell | | Please Replace Regularly To Keep Your Machine Fresh And Clean,For Best Results, Remove The Filter Once A Month And Clean With A Soft Brush Or Gently Vacuum. | | Top-Notch Quality Used For Maximum