Keep your indoor air fresh and free from pollutants with this 3M Filtrete filter. Designed with 3-in-1 Filtrete technology, it attracts and reduces pollutants such as household dust, pollen, lint and bacteria. The fibreglass furnace filter is electrostatically charged to capture both small and large particles. This electrostatic dust filter is washable, which makes it reusable. The dust filter has a 300 microparticle performance rating (MPR), which is compatible for use with high-velocity equipment such as a furnace and HVAC. The fibreglass air filter reduces irritants in the air and aids people with respiratory issues and sensitivities to micro-particles. Each package contains one filter measuring 24 in L x 20 in W x 1 in T.