Filtrete 14"x20"x1" Gray Basic Dust & Lint Pleated Furnace Air Filter. It is electrostatically charged to attract and capture large airborne allergens like pollen, household dust, and lint. Ideal for high velocity heating/cooling systems, it outperforms ordinary fiberglass and washable 1" filters. With a MPR rating of 300, this filter lasts up to 3 months. For residential use only.