Do it Best MERV 8 efficency rated HVAC (Heating Ventilation and Air Conditioning) air filters are 15 times more effective than standard fiberglass filters. Filters remove microscopic particles that can stain walls and furnishings and aggravate seasonal allergies. Protects against ragweed pollen, mold spores, dust mite debris, pet dander, and dust/lint. Low airflow resistance saves on energy costs while still protecting furnace and air conditioning units. Lasts up to 90 days. Blue label.