Enviroflow 24X24X1 (23.75 x 23.75) Pollen and Dust Control (4 Pack) Nominal size 24 x 24 x 1. Actual Size 23.75 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