Filtrete Aftermarket Replacement Filter, fits Filtrete model FAP04. This filter measures approximately 13 x 8 x 1 and has MERV 13 rated filter media. It has electrostatically charged filter media which captures airborne allergens smaller than 1 micron. It also captures particles such as household dust, bacteria, smoke, smog and particles that can carry viruses. It attracts and captures particles that can carry odors. For optimum performance, replace filter every 3 months. This is an aftermarket filter.