Our Tier1 21-1/4 x 23-1/4 x 1 Air Filter MERV 11 comes in a 6-Pack. These pleated high-capacity filters are constructed using electrostatically charged filter media from Kimberly-Clark - a recognized leader in the filtration industry. This 100% synthetic material offers significantly higher particulate efficiency than typical poly/cotton media pleated filters, and captures the smallest and most troublesome airborne particles and allergens, such as particles that carry viruses and bacteria, pollen, mold spores, fine dust and pet dander. The combination of high efficiency and excellent allergen reduction make these the ideal choice for homeowners looking to improve indoor air quality.

• More efficient than our MERV 8 filter, and captures even smaller particles (1-10 microns in size)
• Doesn't promote the growth of bacteria, mold, mildew, or fungi so they're a great choice for families with small children
• Similar to the 3M Filtrete Ultra Allergen filter
• Rated UL Class 2 by Underwriters Laboratories
• Made in the U.S.A.