The AprilAire 210 MERV 11 Air Filter traps airborne contaminants using patented AprilAire Self-Seal Technology. These contaminants include pollen, mold spores, bacteria, pet dander, and dust. By trapping these contaminants, it reduces your cleaning time and frequency at home, and ensures you're breathing clean air for improved wellness. The 210 Air Filter is compatible with AprilAire 1210, 1620, 2210, 2216, 3210, and 4200 Whole-House Air Purifiers as well as 2120, 2200 Air Purifiers and 2200 Space-Gard using the 1213 Upgrade Kit. And with the 12-month filter life, you only need to change once per year.