This filter is 24x30x1 and measures 23.7x29.7x1. Meeting the American Lung Association Health House Indoor Air Quality Guidelines, this filter has a 1250 performance rating and a MERV 11 rating. It captures 90% of large allergens, like mold spores and pet dander, from the air passing through the filter. It also captures microscopic allergens like dust, smoke and smog particles, bacteria, and particles that can carry viruses. This product is 25% more efficient than the Filtrete Micro Allergen Filter and exhibits 15% better airflow then the Filtrete Micro Allergen Filter. The filter lasts up to 3 months. There are no unnecessary antimicrobial chemicals added. Filtrete filtering material will not support the growth of bacteria, mold, mildew or fungi in normal use.