Accumulair Titanium 14x24x1 (13.5x23.5) High Efficiency Allergen Reduction Air Filter/Furnace Filter Nominal Size: 14x24x1. Actual Size: 13.5 x 23.5 x 0.75 MERV 12 Rating Unique mini-pleat design provides greater surface area than standard pleated filters Electrostatically charged fibers capture microscopic allergens smaller than 1 micron Lasts 90 days