True Blue Replacement Air Filter for Trion Air Bear, 20x25x5 Filters are assembled with a heavy duty frame that prevents collapsing of the filter during installation Filters dust, dirt, pollen, pet dander, dust mite debris, microscopic allergens, smoke and smog Reduces dust and dirt build up in air ducts and in air conditioner and furnace system Lasts up to 1 year and has a MERV rating of 11