Filtrete Micro Partical Reduction Filter 800 MPR 12"x36"x1" (5-PACK) Microparticle Performance Rating of 800 Captures large airborne allergens like household dust, pollen,lint, dust mite debris, mold spores Outperforms non-electrostatic filters, comparable fiberglass and washable/reusable filters Keeps furnace or air conditioner running efficiently Pack includes five filters