Captures large particles such as pollen, mold spores, dust, dust mites, and pet hair * Attracts and captures ultra-fine particles like pet allergens, tobacco, bacteria, odors, and particles that may carry viruses * Electrostatically charged media attracts airborne allergens smaller than 1 micron * Fits 12x24x1 opening. Actual Filter Dimensions: 11.5x23.5x1 * Strong and durable frame prevents air bypass, pleat collapse and filter bowing