12X30x1 (11.5 x 29.5) Enviroflow Air Filter (Merv 8 ) (4 Pack) Nominal Size 12x30x1. Actual Size 11.5 x 29.5 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