Enviroflow 12x24x1 (11.75 x 23.75) Air Filter (4 Pack) Nominal Size 12 x 24 x 1. Actual Size 11.75 x 23.75 x 0.75 MERV 8 Rated. Electrostatic pleated media, which performs better than regular fiberglass fibers. Traps dust and allergens such as pollen, mold, pet dander, and dust mites. Each filter lasts up to 90 days Pack of 4 Filters