Filtrete 20x30x1 Air Filter, MPR 300, MERV 5, Clean Living Basic Dust 3-Month Pleated 1-Inch Air Filters, 6 Filters - Amazon.com
Filtrete 20x30x1 Air Filter, MPR 700, MERV 8, Clean Living Dust, Pollen and Pet Dander Reduction 3-Month Pleated 1-Inch Air Filters, 4 Filters - Amazon.com
Filtrete 20-in W x 30-in L x 1-in MERV 14 2500 Smart Premium Allergen and Ultrafine Particle Electrostatic Pleated Air Filter in the Air Filters department at Lowes.com