Ships in case of 6 only. Attracts and captures microscopic particles such as smoke, cough and sneeze debris, bacteria and viruses—and large particles, including lint, household dust and pollen. Outperforms fiberglass, washable and non-electrostatic 3-month pleated 1″ home air filters for your furnace, air conditioner, or HVAC system. Filtrete 1500 MPR (Microparticle Performance Rating) equates to MERV 12. For maximum performance, change your home air filter at least every 90 days for 1″ filters. 12 in x 36 in x 1 in.