14x14x1 (13.75 x 13.75) Enviroflow Air Filter (Merv 8 ) (4 Pack) Nominal Size 14x14x1. Actual Size 13.75 x 13.75 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